If its close, I leave it, if its blatantly noticeable, I redo it. Most of my friends who receive my quilts don't have any idea about quilting so I'm safe there. They just look at all the pieces in the quilt, the quilting itself and think I'm amazing. Why would I want to change their opinion??????
But I am getting better at matching my seams. Just finished 216 3.5 4-patches for a quilt I'm working on. Having the seams nest sure works nicely and pretty much they all matched pretty good. Maybe a few are off but just a scant thread or two but I can live with that.