How Many Buyer Persona Interviews? The Ideal Number

22 minutes on read

Crafting effective buyer personas is essential for targeted marketing, and the number of interviews you conduct significantly impacts their accuracy. Marketing teams commonly use methodologies from organizations like the MarketingProfs training resource to guide persona development. Each interview participant contributes unique insights that shape the final persona, and the insights from these interviews are invaluable for making more effective marketing decisions. Determining how many buyer persona interviews should you aim to complete involves balancing resource constraints with the need for comprehensive data and reliable information. The objective of the process is to gain a deep understanding of your target audience, which allows for a more focused and effective content marketing strategy, that can be deployed through platforms like HubSpot.

Unveiling Your Ideal Customer Through Buyer Persona Interviews

Buyer personas are semi-fictional representations of your ideal customers.

They are based on research and data about your existing and potential customers.

These personas provide a focused lens through which to understand your target audience.

By deeply understanding their motivations, behaviors, and goals, you can tailor your marketing strategies for maximum impact.

The Role of Buyer Personas in Modern Marketing

Buyer personas are not just nice-to-haves; they are essential tools for effective marketing.

They help align your marketing efforts with the needs and desires of your target audience, ensuring that your message resonates and drives results.

With well-defined personas, every marketing decision—from content creation to channel selection—becomes more strategic and targeted.

This leads to improved engagement, higher conversion rates, and a stronger return on investment.

Why Interviews Are Key to Persona Accuracy

While data analytics and market research provide valuable insights, interviews offer a depth of understanding that other methods cannot match.

Direct conversations with your target audience allow you to uncover nuanced motivations, pain points, and decision-making processes that may not be apparent from quantitative data alone.

Interviews provide rich, qualitative data that humanizes your personas, making them more relatable and actionable.

They allow you to go beyond surface-level demographics and delve into the psychological factors that influence customer behavior.

Benefits of Well-Defined Buyer Personas

Investing in the creation of accurate buyer personas yields a multitude of benefits for your business.

Improved Targeting: Personas enable you to precisely target your marketing efforts.

You'll be able to reach the right people with the right message at the right time.

Increased Conversion Rates: By understanding your audience's needs and pain points, you can craft compelling offers and persuasive messaging that resonates with them, driving higher conversion rates.

Enhanced Customer Engagement: Personas allow you to create content and experiences that are tailored to your audience's interests, leading to increased engagement and brand loyalty.

More Efficient Marketing Spend: By focusing your resources on the most promising prospects, you can reduce wasted ad spend and maximize your return on investment.

Qualitative and Quantitative Approaches

Building effective buyer personas requires a blend of both qualitative and quantitative research methods.

Qualitative research, such as interviews and focus groups, provides in-depth insights into customer motivations and behaviors.

It helps you understand the "why" behind the data.

Quantitative research, such as surveys and data analysis, provides statistical validation and helps you identify patterns and trends across your target audience.

By combining these approaches, you can create well-rounded personas that are both insightful and data-driven.

Planning for Success: Defining Objectives and Identifying Key Stakeholders

Before diving into buyer persona interviews, a crucial groundwork needs to be established. This involves setting clear objectives and engaging key stakeholders within your organization. Without this preparation, the interviews risk becoming unfocused and yielding less valuable insights. This section explores these pre-interview planning steps, highlighting the importance of a structured and collaborative approach.

Defining Clear Objectives: The Foundation of Insightful Interviews

The first step in planning is to clearly articulate what you want to learn from these interviews. What are the specific knowledge gaps you're hoping to fill? Are you trying to understand the challenges your customers face, their motivations for choosing your product, or their decision-making process?

Identifying these objectives will shape the direction of your interviews and ensure that you gather the most relevant information. This clarity allows you to craft targeted questions that directly address these uncertainties.

Identifying Knowledge Gaps About Your Target Audience

Begin by pinpointing areas where your understanding of your target audience is lacking. This may involve brainstorming sessions with your team, reviewing existing customer data, or analyzing market trends.

For example, you might want to know:

  • What are the biggest frustrations our customers experience in their roles?
  • What are the key criteria they use when evaluating solutions like ours?
  • What information sources do they trust and rely on?

Formulating Questions to Validate or Disprove Assumptions

Once you've identified your knowledge gaps, formulate specific questions that will help you validate or disprove any existing assumptions you might have about your target audience.

Avoid leading questions that might bias the responses. Instead, focus on open-ended questions that encourage participants to share their thoughts and experiences in their own words.

For example, instead of asking "Do you find our product easy to use?", try asking "Can you describe your experience using our product?"

Involving Key Stakeholders: A Collaborative Approach

Building accurate buyer personas is not a solitary endeavor. It requires the involvement and collaboration of key stakeholders from across your organization. These stakeholders possess valuable insights into your target audience, gathered from their direct interactions with customers.

By involving them in the planning process, you can ensure that the interviews are aligned with the overall business goals and that the resulting personas are comprehensive and representative.

Gathering Insights from Sales, Customer Service, and Marketing Teams

Each department within your organization interacts with customers in unique ways. Sales teams can provide insights into customer needs and pain points during the sales process. Customer service teams can share information about common issues and support requests. Marketing teams can offer perspectives on customer preferences and communication styles.

By gathering input from all three teams, you can gain a holistic understanding of your target audience. Organize meetings or create surveys to collect their insights and perspectives.

Ensuring Alignment Across Departments

Bringing together these insights can help ensure everyone is on the same page. Misalignment can lead to inefficient marketing and sales efforts. By creating a shared understanding of the target audience, you can improve communication and collaboration across departments.

This shared understanding will ultimately lead to more effective customer engagement and improved business outcomes.

Selecting Interview Candidates: A Strategic Approach

The selection of interview candidates is critical to the success of your buyer persona research. You need to choose participants who accurately represent your target audience and can provide valuable insights. This requires a strategic approach to identifying and recruiting the right individuals.

Prioritizing Relevance to Your Target Audience

When selecting interview candidates, prioritize individuals who closely match your ideal customer profile. Consider factors such as their industry, job title, company size, and purchasing power. You want to ensure that you're interviewing people who are representative of the customers you're trying to reach.

Including Diverse Perspectives

To gain a comprehensive understanding of your target audience, it's essential to include diverse perspectives in your interviews. This means interviewing existing customers, potential customers, and even lost leads. Existing customers can provide insights into their experience with your product or service. Potential customers can offer perspectives on their needs and challenges.

Lost leads can shed light on why they chose not to purchase from you.

By including these diverse perspectives, you can gain a more nuanced understanding of your target audience and develop more accurate buyer personas.

Crafting the Conversation: Developing Your Interview Guide

Having identified your interview objectives and assembled your stakeholder team, the next pivotal step is designing a robust interview guide. This guide serves as your roadmap, ensuring you gather the critical insights needed to build accurate buyer personas. However, it's crucial to strike a balance: the guide must be structured enough to maintain focus, yet flexible enough to allow for organic conversation and unexpected discoveries.

Structuring the Interview: Embracing the Semi-Structured Approach

The most effective approach to buyer persona interviews is semi-structured. This means having a clear set of questions, but also allowing the conversation to flow naturally.

A rigid, highly structured interview feels more like an interrogation and less like a genuine conversation, potentially hindering the respondent's willingness to share openly.

Conversely, a completely unstructured approach can lead to meandering discussions that yield little actionable information.

The semi-structured approach provides the best of both worlds. It provides a framework while allowing for flexibility.

The Power of Open-Ended Questions

The cornerstone of a successful interview guide lies in the artful crafting of open-ended questions. These questions encourage participants to elaborate on their experiences, motivations, and challenges, providing rich qualitative data.

Instead of asking "Do you use social media for work?" (a closed-ended question), try "How does social media fit into your daily workflow?"

This invites a more detailed response.

Similarly, instead of asking "Are you satisfied with our product?", consider "What are your favorite aspects of our product, and what areas do you think could be improved?"

These types of questions are designed to elicit in-depth, nuanced answers.

Uncovering Motivations, Challenges, and Decision-Making Processes

Your interview guide should be strategically designed to uncover the core drivers behind your target audience's behavior. Focus your questions on understanding their:

  • Motivations: What are their goals, aspirations, and desires? What truly drives them?
  • Challenges: What obstacles do they face in achieving their goals? What are their pain points and frustrations?
  • Decision-Making Processes: How do they research and evaluate potential solutions? Who is involved in the decision-making process? What factors influence their final choice?

Questions such as "What are the biggest challenges you face in your role?" or "Walk me through the process you typically follow when making a purchase decision like this" are excellent starting points.

Qualitative Research Principles: Guiding Your Approach

Beyond the structure of the questions, your interview guide should also reflect fundamental principles of qualitative research. These principles are essential for maximizing the depth and richness of the insights you gather.

Emphasizing Exploratory Questions Over Leading Questions

Avoid leading questions at all costs. These questions subtly (or not so subtly) suggest a desired answer, biasing the participant's response.

For example, instead of asking "Don't you agree that our product is the best solution for this problem?", ask "What other solutions have you considered, and how do they compare?"

This approach encourages honesty.

Instead of feeding ideas or perceived assumptions, allow the respondent to arrive at their own conclusions.

This will result in authentic and valuable feedback.

Allowing for Tangents and Deeper Dives

While structure is important, don't be afraid to deviate from your interview guide if the conversation leads to an interesting or unexpected area.

Sometimes, the most valuable insights emerge from unplanned tangents.

If a participant mentions a particular challenge or experience that resonates with you, seize the opportunity to explore it further. Ask follow-up questions, encourage them to elaborate, and delve deeper into the topic.

This approach demonstrates genuine curiosity and can unlock hidden gems of information that might otherwise have been missed. Remember that your interview guide is a guide, not a rigid script. Embrace the fluidity of conversation and allow it to lead you to a deeper understanding of your target audience.

Logistics and Preparation: Setting the Stage for Insightful Interviews

Having crafted a compelling interview guide, the next critical phase involves meticulous logistical planning and preparation. This stage sets the foundation for a smooth, productive, and insightful interview process. Overlooking these details can lead to missed opportunities and unreliable data.

Effective logistics are not merely about scheduling; they're about creating an environment conducive to open communication and honest feedback. This entails carefully coordinating interview times, clearly communicating expectations, and ensuring you have the right tools at your disposal.

Scheduling and Communication: Respecting Participants' Time

The initial interaction with potential interviewees significantly impacts their willingness to participate and their level of engagement during the session. Approach scheduling with respect and clarity.

  • Coordinating Interview Times: Offer a range of time slots to accommodate participants' schedules. Use a scheduling tool to streamline the process and minimize back-and-forth communication. Flexibility is key.

  • Clearly Communicating the Purpose and Structure: In your invitation, explicitly state the interview's objective and how the gathered information will be used. A clear explanation alleviates concerns about privacy and reinforces the value of their contribution. Transparency builds trust.

  • Providing Necessary Information: Equip participants with details about the interview format (e.g., phone call, video conference), duration, and any preparation required. This proactive approach demonstrates professionalism and reduces anxiety. Send a reminder email a day or two before the interview. Thoughtful communication enhances the participant experience.

Securing Tools: Equipping Yourself for Success

Beyond scheduling, having the right tools is crucial for efficiently capturing and analyzing interview data. Choosing reliable software and equipment streamlines the process and ensures accuracy.

  • Choosing Transcription Software: Accurate transcription is essential for thematic analysis and persona development. Invest in a reputable transcription service or software that automatically converts audio to text. Accuracy is paramount. Review the generated text, fixing grammar and vocabulary errors. Doing this minimizes the chance of a missed point.

  • Selecting a Reliable Video Conferencing Platform: For remote interviews, a stable and user-friendly video conferencing platform is vital. Ensure the platform offers screen sharing capabilities, recording options, and a clear audio connection. Test the equipment before the interview. Technical glitches can disrupt the flow of the conversation and frustrate both parties. Have a plan B to deal with problems.

Conducting the Interview: Building Rapport and Gathering Insights

Having crafted a compelling interview guide, the next critical phase involves meticulous execution of the interviews themselves. This section emphasizes the art of building rapport, the importance of active listening, and the necessity of thorough documentation to ensure that valuable insights are captured effectively. Overlooking these crucial aspects can compromise the entire buyer persona development process, leading to skewed or incomplete understandings of your target audience.

Establishing a Foundation of Trust and Comfort

The initial moments of the interview are paramount for setting the tone. Creating a comfortable and trusting environment is essential for encouraging participants to share their honest thoughts and experiences.

  • The Importance of First Impressions: Begin by clearly introducing yourself and the purpose of the interview. Be transparent about how the information will be used and emphasize that their opinions are valued.

  • Putting Participants at Ease: Acknowledge their time and express gratitude for their participation. A friendly and approachable demeanor will help alleviate any anxieties and encourage openness. Share a brief overview of the interview structure, so the participant knows what to expect.

  • Non-Verbal Communication: Remember, non-verbal cues speak volumes. Maintain eye contact, offer encouraging nods, and use a warm, inviting tone of voice to convey genuine interest and respect.

The interview guide serves as a roadmap, but it should not be treated as an inflexible script.

  • Embrace the Unscripted: While it's important to cover the key questions outlined in your guide, allow for flexibility to explore interesting tangents and delve deeper into specific areas that emerge organically.

  • The Art of Probing: Don't be afraid to deviate from the script if the conversation leads to valuable insights. Ask follow-up questions to gain a more comprehensive understanding of their perspective.

  • Guiding the Conversation: It’s your job to guide the conversation back to the core objectives if it veers too far off course. Gently redirect the participant while acknowledging their contribution.

The Power of Active Listening

Active listening is more than just hearing; it's about demonstrating genuine interest in what the participant is saying and ensuring that you fully understand their message.

  • Paying Attention: Focus your attention on both verbal and non-verbal cues. Observe their body language, tone of voice, and facial expressions for additional context.

  • Clarifying and Summarizing: Ask clarifying questions to ensure you understand their perspective. Summarize key points to confirm your understanding and give them an opportunity to correct any misinterpretations.

  • Empathetic Engagement: Show empathy and understanding by acknowledging their feelings and experiences. Use phrases like "That sounds frustrating" or "I can understand why you feel that way." This creates a stronger connection and encourages them to open up further.

Capturing Insights: Recording and Documentation

Thorough documentation is crucial for preserving the valuable insights gleaned during the interview.

  • Ethical Considerations: Always obtain explicit consent to record the interview for accurate transcription and analysis. Assure participants that their responses will be kept confidential and used solely for the purpose of developing buyer personas.

  • The Value of Note-Taking: Even with a recording, take detailed notes during the interview to capture important details that may not be apparent in the recording, such as emotional cues or specific phrases.

  • Organizing Your Notes: Develop a consistent system for organizing your notes, such as using keywords or color-coding, to facilitate easy retrieval and analysis later on.

By mastering the art of building rapport, adapting to the flow of conversation, practicing active listening, and meticulously documenting insights, you can transform buyer persona interviews from mere question-and-answer sessions into powerful vehicles for understanding your target audience on a deeper level. The results will translate to more effective marketing strategies and stronger customer relationships.

Analyzing the Data: Identifying Themes and Validating Findings

Having crafted a compelling interview guide and executed the interviews with precision, the subsequent critical phase involves meticulous data analysis. This section outlines the essential processes of transcribing interview recordings, identifying recurring themes within the data, determining data saturation, and, finally, validating the qualitative findings with quantitative methods. This comprehensive approach ensures that the insights gleaned are both insightful and reliable, forming a solid foundation for your buyer personas.

From Audio to Text: The Importance of Accurate Transcription

The first step in data analysis is transcription: converting the audio recordings from your interviews into written text. This may seem like a straightforward task, but accuracy is paramount.

Even subtle nuances in language can significantly impact your interpretation of the data.

Transcription software, readily available, can expedite this process considerably. However, always review the automatically generated transcript for errors and inconsistencies. Invest time in accurate transcription; it's a cornerstone of reliable analysis.

Uncovering Patterns: Theme Identification in Qualitative Data

Once you have accurate transcripts, the real analysis begins: identifying themes.

This involves carefully reading through each transcript and looking for recurring patterns in the responses.

These patterns may relate to common pain points, frequently mentioned motivations, or similar approaches to decision-making. Consider using qualitative analysis software to tag and organize the data, highlighting connections between participant responses.

Be vigilant about potential biases. As the analyst, it’s easy to unintentionally impose your own assumptions on the data. Adopt a systematic approach, and document your reasoning for each identified theme to ensure transparency and objectivity.

Knowing When to Stop: Data Saturation and Interview Sufficiency

A key question throughout the interview process is: "How many interviews are enough?" The concept of data saturation provides the answer.

Data saturation is reached when conducting additional interviews yields minimal new information or insights. You start hearing the same themes repeated, indicating that you've captured a comprehensive view of your target audience.

While there's no magic number of interviews to conduct, monitoring the emergence of new themes will guide you. Aim for a sample size that allows you to confidently identify and validate key patterns.

Validating Insights: Supplementing Qualitative Data with Quantitative Methods

While qualitative data offers rich, nuanced insights, it's essential to validate those findings with quantitative data. This can be achieved through surveys or other quantitative methods.

For example, if your interviews reveal that a significant portion of your target audience struggles with a particular challenge, you can design a survey to quantify the prevalence of that challenge across a larger sample.

Quantitative validation provides statistical evidence to support your qualitative findings, increasing the credibility and actionability of your buyer personas. This combined approach provides a holistic and trustworthy understanding of your target audience.

Creating Your Buyer Personas: Synthesizing Data into Actionable Profiles

Having crafted a compelling interview guide and executed the interviews with precision, the subsequent critical phase involves meticulous data analysis. This section outlines the essential processes of transcribing interview recordings, identifying recurring themes within the data, determining the point of data saturation, and validating the insights with supplementary quantitative data. With the analytical groundwork laid, the real power lies in translating this raw information into tangible, actionable buyer personas.

The process isn't merely about compiling data; it's about weaving a narrative that embodies the essence of your target audience, breathing life into abstract data points. This section will guide you through the nuanced art of transforming research findings into detailed, resonant persona profiles that will serve as invaluable guides for your marketing and business strategies.

Data Synthesis: Weaving the Threads Together

The initial step involves meticulously synthesizing all the insights gleaned from the interviews and any supplementary data you've gathered. This is where you transform a collection of individual observations into a cohesive understanding of your customer.

Consolidating Key Insights

The objective is to distill the essence of your research into a concise and compelling persona document. This means carefully curating the most revealing quotes, identifying the most pressing pain points, and highlighting the most influential motivations that emerged across your interviews. Consider using a spreadsheet or dedicated persona software to organize and categorize these insights.

By consolidating the findings, you are essentially creating a single source of truth that can be readily accessed and understood by anyone within your organization. This ensures that everyone is working from the same foundational understanding of the target audience.

Persona Profile Development: Building a Comprehensive Picture

With the key insights synthesized, the next step is to create detailed profiles for each of your buyer personas. This is where you flesh out the skeletal framework of your target audience with concrete details and relatable characteristics.

Essential Elements of a Persona Profile

Each profile should encompass a range of elements, including:

  • Demographics: Age, gender, location, income, education, and other relevant demographic information.

  • Psychographics: Values, attitudes, interests, lifestyle, and other psychological attributes.

  • Motivations: The driving forces behind their decisions, both professional and personal.

  • Challenges: The obstacles and frustrations they encounter in their work and daily lives.

  • Goals: What they are trying to achieve, both short-term and long-term.

  • Job Title & Responsibilities: What is their role and what does their day-to-day look like.

  • Technology Adoption: Which technologies do they use for work and personal?

  • Preferred Communication Channels: What are the preferred modes of engagement for this persona?

  • Information Sources: Where do they consume information and research products?

  • Sales Preferences: What kind of buying experience does this persona prefer?

These elements will help your team understand your customers and prospects, leading to a more effective marketing strategy.

Incorporating Quotes: Adding Authenticity and Relatability

One of the most powerful ways to bring your buyer personas to life is to incorporate direct quotes from your interviews. These quotes provide a voice for your target audience, adding a layer of authenticity and relatability that cannot be achieved through demographic data alone.

Strategic Use of Direct Quotes

When selecting quotes, choose those that are particularly insightful, evocative, or representative of a common sentiment expressed by your interview participants. Use these quotes strategically within the persona profiles to highlight key pain points, motivations, or decision-making processes.

For instance, instead of simply stating that a persona is frustrated with their current software, include a quote like, "I spend more time wrestling with the software than I do actually using it to solve problems." This quote not only reinforces the pain point but also adds a human element that resonates with the reader.

Review and Refinement: Ensuring Accuracy and Relevance

The final step in creating your buyer personas is to share the draft profiles with key stakeholders across your organization and solicit their feedback. This collaborative process helps to ensure the accuracy and relevance of the personas, as well as fostering buy-in from the teams that will be using them.

Gathering Diverse Perspectives

Present the draft personas to the sales, customer service, and marketing teams. These teams interact directly with customers and can provide valuable insights into whether the personas accurately reflect their experiences. Encourage them to challenge assumptions, fill in gaps, and offer alternative perspectives.

By incorporating feedback from these stakeholders, you can refine the personas to create truly representative and actionable tools that will empower your organization to connect with your target audience on a deeper level. This iterative process is key to ensuring the ongoing value and relevance of your buyer personas.

Ongoing Refinement and Application: Keeping Your Personas Relevant

Having crafted compelling buyer personas through careful interview strategies and meticulous data analysis, the work doesn't simply end there. Buyer personas are not static artifacts. They need continuous nurturing and consistent application to stay valuable. This section underscores the necessity of regular updates, comprehensive integration into organizational decision-making, and the importance of ensuring everyone understands their role. This will sustain their effectiveness over time.

The Imperative of Regular Persona Updates

Buyer personas are reflections of a dynamic reality.

Markets shift, customer preferences evolve, and your business adapts. Failing to reflect these changes in your personas renders them obsolete.

Regularly revisiting and revising your personas is not just a good practice; it is essential for maintaining their accuracy and relevance.

Consider setting a review schedule – perhaps quarterly or bi-annually.

Also, be sure to trigger a review whenever you witness a significant shift in the market or customer behavior. This ensures that your personas continue to accurately represent your target audience.

Integrating Personas into Decision-Making

Driving Strategic Alignment

The true power of buyer personas lies in their ability to inform and align various aspects of your business.

From marketing and product development to sales and customer service, personas can serve as a guiding compass.

Integrating personas into decision-making ensures that every initiative is rooted in a deep understanding of your target audience.

This includes tailoring marketing messages, designing products that meet their specific needs, and crafting sales strategies that resonate with their motivations.

Mapping the Customer Journey

Delving into the customer journey for each persona provides valuable insights into their experiences and interactions with your brand.

By understanding their pain points, touchpoints, and decision-making processes, you can optimize the customer experience at every stage.

This detailed journey mapping helps you to anticipate their needs, address their concerns, and deliver personalized experiences that foster loyalty and advocacy.

Cultivating Organization-Wide Understanding

Accessible Personas

For buyer personas to be effective, they must be readily accessible and easily understood by everyone in the organization.

Creating a centralized repository where personas can be accessed and shared ensures that all relevant teams have the information they need.

This can be a shared drive, a dedicated platform, or even printed posters in common areas.

The key is to make the information readily available and easy to digest.

Training and Education

Beyond accessibility, it is crucial to ensure that employees understand how to use the personas effectively.

This may involve conducting training sessions, workshops, or creating educational materials that explain the purpose of personas and how they can be applied in different contexts.

By investing in training and education, you empower your employees to make informed decisions that are aligned with your target audience's needs and preferences.

In conclusion, keeping buyer personas relevant requires a proactive approach. Embrace a process of continuous refinement, strategic integration, and organization-wide adoption to maximize their impact on your business.

FAQs: Buyer Persona Interview Quantity

Why is the number of buyer persona interviews important?

Having enough interviews ensures you uncover recurring patterns and avoid basing personas on outliers or limited viewpoints. Fewer interviews increase the risk of inaccurate or incomplete personas. Understanding this data well is crucial for effective marketing and product development.

What's the magic number for buyer persona interviews?

While there's no one-size-fits-all, aim for 5-10 interviews per persona. This range typically allows you to identify common pain points, motivations, and behaviors within a specific segment. To determine how many buyer persona interviews should you aim to complete, start with 5, and then evaluate if you're still hearing new information.

How do I know when I've done enough interviews?

You've likely reached saturation when you consistently hear similar responses and aren't uncovering new insights. The point of diminishing returns is a good indication that you've gathered sufficient information. If insights begin to repeat, you’ve likely completed an adequate number of interviews.

Does the number of buyer personas impact the total interview count?

Yes, each persona requires its own set of interviews. If you are creating three distinct buyer personas, you would ideally conduct 15-30 interviews in total. Remember, how many buyer persona interviews should you aim to complete depends on the unique attributes of each specific persona.

So, there you have it! Figuring out how many buyer persona interviews you should aim to complete really boils down to the complexity of your target audience and the resources you have available. While there's no magic number, aiming for at least 5-10 interviews per persona will give you a solid foundation. Now go forth and chat with your customers – you might be surprised what you learn!