> Wherever you think is the right effort/benefit threshold, it will turn out to be different in a few weeks.

Very true. And experiencing this has absolutely been a useful lesson to me. I remember feeling pained over some code I wanted to write in a more robust and principled way in front of a big deadline, and after a bit of friendly push and pull with my manager, I agreed to console myself by throwing in some TODOs and FIXMEs in the comments instead of getting carried away overengineering or burning rubber just beautifying my style. I remember this ritual feeling painful at the time, though it helped me cross the finish line sooner. A few months later, it was clear that ~80% of that code would be good enough for the next year or so— by which time other parts of the application would have evolved as well. I even ended up glad I'd deferred a few of those changes just so the small refactors could be informed by things we'd learned in the meantime.

Sometimes it goes the other way, or course! Many times I've been glad for some extra care I put in early, or regretful about some I didn't. But you're right that that balance always seems to change in retrospect, one way or the other.