Direct customer interviews are the highest-signal diligence step you can run. They're also the most dangerous to confidentiality. Done right, you talk to 5–10 customers in a way that surfaces real issues without leaking the sale.
The cover story. Position yourself as a "service quality auditor" or "consultant doing a customer satisfaction review for [seller's company]." The seller introduces you in advance via email, with their endorsement. You are NOT the buyer until close.
Who to call. Mix: top 5 accounts by revenue, 2–3 newest accounts (last 6 months), 2–3 longest-tenured (5+ years), 2–3 from the cancellation log if reachable. The cancelled customers tell you the most.
The script. Open: "Hi, I'm doing a service review for [seller]. Got 3 minutes for some quick questions?" Then:
1. How long have you been a customer?
2. What's working well?
3. What's one thing you'd improve?
4. Any service interruptions in the last year?
5. (For commercial/HOA) Are you under contract? When does it renew? Have you considered switching?
What you're listening for. Genuine warmth = strong relationship that will likely transfer. Lukewarm responses = at-risk account. Anyone who says "honestly we've been thinking about switching" is gone within 6 months regardless of who owns the route. Adjust your offer accordingly.
Red flag patterns. Multiple customers mention the same complaint (missed weeks, billing errors, slow response). Anyone who didn't know they were on weekly service. Commercial accounts whose decision-maker has changed without the seller knowing.