The point where a product solves a real problem well enough that people keep using it and tell others — growth starts pulling instead of being pushed.
Scaling before fit is the most expensive mistake in software: you spend the budget hardening, hiring, and marketing around a product nobody is retained by.
We treat the first release as a test with a stated hypothesis and a retention number that would disprove it, and we plan the budget so there is room to change direction after that answer.