"Don't build what you can buy" is good advice — until it quietly caps your business. With AI now a third option, the honest version is: buy your commodities, build your differentiators, and use AI where the problem is genuinely fuzzy.
A simple framework
- Buy when the capability is undifferentiated — payroll, auth, payments. Vendors do it better than you will.
- Build when the capability is the business — the workflow or experience customers pay for.
- Use AI when the task is high-variance and hard to specify — summarisation, classification, natural-language interfaces — not when a deterministic system would do it better and cheaper forever.
The trap isn't building too much. It's buying your differentiator, building your commodities, and using AI for things plain code should own — all at once.
Most strong systems are a blend: bought components for the undifferentiated 80%, custom code for the 20% that makes you you, and AI carefully placed where it earns its ongoing cost.
Sources
- MIT NANDA — The GenAI Divide
Written by ivector
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