Build or Buy: Do the Math First
Added 2026-10-30
Compare total cost, maintenance burden and exit cost of building versus buying.
We are deciding whether to build or buy a capability. I will give requirements, rough build cost, vendor price, team size, and how important this capability is. Do: 1) 12-month total cost for each path including people, maintenance and migration; 2) which path gets more expensive when requirements change; 3) a small build-to-validate path with success metrics; 4) if we buy, the three exit clauses that must be in the contract. Put key numbers in a table.
Site original
Chinese original
How to use
自建的真实成本不在开发，而在之后的每一年。
Try tweaking it
- Have it state how the hypothesis could be falsified before discussing execution.
- Split the plan into a one-week testable experiment.
What you should get
- A small testable experiment with a failure threshold
- Costs, risks, and what needs outside confirmation
Common mistakes
- Asking for a "full business plan" and getting unverifiable optimistic assumptions.
- No failure threshold, so you never know whether to continue.
How to check the output
- There is a clear failure threshold, testable within a week.
- Costs, assumptions and risks are listed separately.
Where it works
- Good for: turning business assumptions into a small testable experiment with a failure threshold first.
- Watch out: for pricing, contracts and legal points, treat output as a draft needing professional review.