At what point is an MVP feature "done enough" to stop touching it?

I'm building the core feature of my product right now, and I keep noticing the same pattern.

I start on the one thing the product is supposed to do, and while building it, small necessary-looking pieces attach themselves. An empty state needs handling. Errors need messages. Settings need a place to live. None of these feel optional in the moment, but a week later I look up and I've spent most of my time on the branches instead of the trunk.

So my question is about where you draw the line while you're still in the middle of building.

How complete does the core feature need to be before you call it done for the MVP? Do you deliberately ship it rough — no empty states, ugly errors, no settings — and fix it only if users complain? Or is there a minimum level of finish below which people won't even try it?

And more practically: how do you tell the difference between a side branch that's actually load-bearing and one that just feels urgent because you're staring at it?