I'm pretty fussy but sometimes a seam slips through that I don't like and don't catch in time and now I leave it. There have been years when I would take apart all sorts of things to fix a 1/8" off seam, but not any more. With my vision issues if I ever find the problem again I'd probably do more damage trying to take out rather than put in.
I tend to sew a bit scant and some things like HST I make deliberately big and trim down, so my usual fudging is trimming down.
My tolerance is much higher than what it was when I started quilting but that was before rotary cutters and such and I used paper patterns. Then I pretty much just went with whatever I had and I would have a lot of very different things to put together! But I would try to get the blocks go together as well as possible so that the rows would go together. Was still using yarn ties back then as well, didn't seem so crucial to have everything exactly match.