The earlier in the recording flow-chart the changes are made, the better IMO. All the way back to retracking. But how often can (will) one do THAT?But then once you notice said problems (too much bass, sizzly cymbals, etc), do you go back in the mix and fix those things, since you have the option of re-editing your own, individual tracks - vs. a mastering house where they are forced to apply such changes over the entire mix?
I would assume you'd apply to specific tracks to fix said problems, since you have the option - its how I do it - but who knows. S'why Im askin!