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Commercial Due Diligence Customer Interviews: Questions for Growth, Retention, and Switching Costs
Five things customer interviews should test in commercial due diligence, with the questions to ask for each.
Qualitate Team
Customer interviews in commercial due diligence should test five things: where growth comes from, why customers renew, how hard it is to switch, how much pricing power the company has, and how much customers depend on the product. Each one maps to an assumption in the investment case.
The strongest evidence comes from specific decisions. A customer who explains what they bought, which alternatives they considered, and what happened at the last renewal gives the deal team something to check against company records.
Qualitate runs these interviews for private equity teams. Its AI Interviewer speaks with current customers, churned customers, and former employees, and a custom project typically completes 20 to 25 interviews in 3 to 10 business days. One top-10 global PE firm went from an initial question to completed interviews with 25 churned customers and 25 former employees in eight business days.
Turn the thesis into questions you can test
Start with the assumptions that would change your assessment if they proved wrong. For each one, specify the customer experience that could support it and the evidence that would challenge it.
The following matrix is a research-planning template. Its claims are illustrative.
| Illustrative thesis claim | Customer question | Evidence that would challenge it |
|---|---|---|
| Existing-account expansion can support the forecast on the planned timetable | Which additional teams or use cases have you actually funded? | The customer has no approved expansion budget, or implementation constraints push the project beyond the forecast period. |
| Renewals reflect strong customer value | What happened during your most recent renewal decision? | The customer reduced scope, deferred a replacement, or stayed only until a contract milestone. |
| Switching is difficult | Walk me through the work required to replace the product. | A recent switcher moved essential workflows with limited disruption. |
| The business has pricing power | How did your organization respond to the latest price change? | Higher rates led to discounts, fewer units, downgrades, or an alternative purchase. |
Keep the initial guide consistent across comparable customers. Add probes where an answer raises a new issue, and retain evidence that conflicts with your original view.
Choose participants who can explain the decision
Build the sample around the questions. Recent buyers can explain selection and onboarding, established customers can describe use and renewal, and churned accounts can reconstruct an exit. Where relevant, include lost prospects, buyers who made no purchase, and customers of alternatives.
Churned customers and lost prospects are usually the hardest people to reach, and they often explain the most. Qualitate can interview experts from its own vetted Expert Panel or a list you supply, including current customers, churned customers, and former employees.
Aim for coverage of the segments that matter to the thesis, including company size, use case, geography, and purchasing route. Track who was invited, who participated, and how they were sourced. A set of management-selected references can offer useful detail, but it leaves other customer experiences unobserved.
Screen for firsthand involvement. Ask when the respondent last evaluated, approved, used, or renewed the product. A procurement lead may know the commercial terms while a user understands workflow dependence. Record those perspectives separately.
Agree the contact route, permitted topics, and recording arrangements before recruitment.
Questions to ask customers during commercial due diligence
Begin with the purchase or renewal the participant knows best. Establish dates, role, product scope, and the outcome before asking for explanations. The following questions are a starting guide to adapt to the business.
Growth and expansion
- What triggered the original purchase, and which budget funded it?
- How has your use changed since then? Which teams or workloads were added or removed?
- What additional use cases have you evaluated, and what has been approved?
- What would have to happen internally for spending to increase?
Separate opportunities a buyer can imagine from projects with an owner, approval, and timing. Ask about constraints such as implementation capacity, competing priorities, and unused capacity in the existing contract.
Retention and renewal
- Walk me through the most recent renewal, from preparation to the final decision.
- Which alternatives, including doing less or doing the work internally, were considered?
- What changed in the package, usage, or commitment?
- What concerns remain, and when will the organization review them?
A renewal can coexist with reduced usage or an intention to replace the product later. Establish the outcome and its timing, then compare the account with the company’s renewal and revenue records.
Switching costs
- Which systems, data, and workflows would need to change if you replaced the product?
- Has your team estimated or tested that work? What did it involve?
- For a completed switch, how did the actual time, cost, and disruption compare with your expectations?
- Which obstacles came from implementation, contractual commitments, or the availability of alternatives?
Distinguish a buyer’s expectation from a completed migration. Interview recent switchers where possible, and examine whether the same obstacles apply to different customer segments.
Pricing and perceived value
- How did the latest offer differ from the previous agreement?
- Which changes reflected the rate, quantity, package, discount, or contract term?
- How did you respond, and what did your organization ultimately commit to?
- Which outcomes made the expenditure worthwhile, and which were difficult to demonstrate?
Keep announced increases, quoted terms, and the buyer’s reported final commitment separate. The B2B pricing benchmarking guide provides fields for comparing offers on a consistent basis.
Product dependence and alternatives
- Which activities would be affected if the product were unavailable?
- What workarounds have you used, and how well did they perform?
- Which alternatives reached a serious evaluation, and what decided the outcome?
- Which uses have you kept, expanded, or reduced, and what drove those decisions?
Ask for a concrete event or workflow behind words such as essential, differentiated, or easy to replace. Establish which people experienced the effect and whether it applied to the whole deployment or one part.
Probe without leading the customer
Use short probes that invite detail: What happened next? Which alternative did you compare? Who participated in that decision? What can you describe from firsthand experience?
Illustrative example: a customer says they renewed because migration would be disruptive. Ask which migration tasks they assessed, who assessed them, and whether the team tested an alternative. An account based on an implementation assessment supports a different conclusion from a general concern nobody investigated.
Keep hypothetical responses separate from decisions already made, and follow contradictory answers until the difference is understood or clearly marked unresolved. Qualitate’s AI Interviewer follows a guide your team approves and adapts its follow-up questions to each answer.
Connect interview findings to the wider evidence
Create an evidence record for each finding: the thesis assumption, respondent role and segment, interview date, decision date, supporting passage, conflicting evidence, and the next verification step. Qualitate’s briefings link each finding to the underlying transcript, so that record starts with the source attached.
Compare growth accounts with usage and expansion records, renewal explanations with retention data, and pricing accounts with realized revenue and contract changes. ICAEW’s guideline describes commercial due diligence as combining primary research, secondary research, and internal information.
Report the sample and how it was selected. A targeted interview program reveals the mechanisms behind customer behavior. Customer-wide churn rates and market size come from company records and market data.
Frequently asked questions
What should customer interviews test during commercial due diligence?
Five things: the source of growth, the reasons customers renew, the real cost of switching, the company’s pricing power, and how much customers depend on the product. Each interview should tie a specific customer decision to one of those assumptions in the investment case.
How many customer interviews are enough?
A typical starting point is 20 to 25 interviews for each customer segment that matters to the thesis. Add more when new interviews are still changing the explanation, or when a segment such as churned customers is missing.
Should interviews include former customers?
Yes, when retention, switching, or competitive losses matter to the thesis. Compare their experience with renewers and recent buyers, and note differences in timing and segment.
Can interviews validate a revenue forecast?
They test the customer behavior behind the forecast’s assumptions. Assess those findings alongside historical revenue, customer-level records, market data, and the other diligence workstreams.
Test your investment thesis with customer evidence
Qualitate is trusted by 7 of the top 20 private equity firms by AUM. Bring the assumptions you need to test, and you’ll see the proposed interview guide, the customers and former employees we can reach, and a sample briefing with every finding linked to its transcript. For a wider view of the options, see our comparison of B2B primary research platforms.
