Looking at the builds I have done, guitars or what ever, I can always spot errors. So in that sense I guess I leave them. But they are mostly something I didn't see while building. Or in some cases I think I chose not to see them That said, if make a cutting mistake I generally either fix it or redo the piece. Or change the plan and redesign so that the mishap gets removed.
On my padouk top single cut I was trying to force myself to get it finished. When I was almost there I dropped my reading glasses on the top which got a small dent. I have no idea how the glasses could have done the dent so maybe it was already there and I only noticed it when I dropped the glasses. Anyway, I first thought I would just leave it there. But couldn't, so I scraped the area, sanded the dent down and spent several days applying shellac to fix it. Now that I have playing the guitar carelessly awhile there are already a couple of bigger dents on it. So was the fix worth it? In my opinion it was