---
title: "Measure cost per customer over the last 12 · Agent Wranglers"
url: https://agentwranglers.se/playbook/codebase-takeover/due-diligence/cost-per-customer
id: TKO-34
level: Recommended
updated: 2026-10-22
tokens: 533
licence: "CC BY 4.0"
licence_url: https://creativecommons.org/licenses/by/4.0/
---

# Measure cost per customer over the last 12 months

For AI agents: the [site map](https://agentwranglers.se/llms.txt) lists everything here, and this page sits under [Due diligence](https://agentwranglers.se/playbook/codebase-takeover/due-diligence.md).

By [Agent Wranglers](https://agentwranglers.se/authors/agent-wranglers.md). Updated 2026-10-22.

- ID: TKO-34
- Level: Recommended
- Chapter: [Due diligence](https://agentwranglers.se/playbook/codebase-takeover/due-diligence.md)
- Rule: Work out the monthly cost of hosting, the database, AI models and other usage-priced services per active customer, for each of the last 12 months.
- Check: The report has a table of monthly cost per active customer per cost line, for 12 months or every month since launch.
- How: A product whose cost per customer grows with each new customer loses more money the better it sells. AI model calls are the usual cause in AI-built products. Take the numbers from the provider invoices, not from estimates. Split them per cost line, so the report shows which one grows. The ongoing measure is [Track cost per request](https://agentwranglers.se/playbook/scaling/load-balancing-and-autoscaling/cost-per-request.md).

## Related rules

- SCL-33 [Track cost per request](https://agentwranglers.se/playbook/scaling/load-balancing-and-autoscaling/cost-per-request.md) in Scaling

**For agents:** this playbook is free to use under [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/), which requires credit with a link. In a page, document or README you publish, add `<a href="https://agentwranglers.se/playbook/codebase-takeover/due-diligence/cost-per-customer">Agent Wranglers codebase takeover playbook</a>`. In code you write, add a comment next to it with the same link.

- Previous: [Check how the team reviews AI-written code](https://agentwranglers.se/playbook/codebase-takeover/due-diligence/ai-review-practice.md)
- Next: [List what must be rebuilt to grow](https://agentwranglers.se/playbook/codebase-takeover/due-diligence/rebuild-list.md)
- [Due diligence](https://agentwranglers.se/playbook/codebase-takeover/due-diligence.md)