When does a vibe-coded product actually need an engineer?

Vibe coding is great until your product has real users. Then the "vibe" hits a wall. Slow queries. Weird bugs. Features that break other features. You can patch it for a while. But eventually, the tech debt catches up.

At what point do you stop vibing and bring in someone who actually knows what they're doing?

Is it:

• When you hit 10 paying users?

• When the app crashes more than once a week?

• When adding a new feature takes longer than building the MVP?

Or do you just keep vibing and hope it holds together? Curious where other makers draw the line.