When to Modularize: The Christensen Timing Framework

Clayton Christensen showed that when a product becomes good enough, the basis of competition shifts from performance to flexibility. Before PMF, integration lets you iterate fast. After PMF, integration becomes a liability. Every feature you add to an interdependent system increases complexity and slows you down.

PMF and the decoupling point happen at the same time, but leaders celebrate PMF as a revenue victory and miss that the architecture is becoming a liability. Success doesn't mean more of the same. The rules changed. The companies that survive learn the new rules. The ones that don't keep building features in the same messy system that got them there.