I cannot count the number of times that I've thought to myself while cleaning some trivial detail up, "Is this really worthwhile? Am I really going to care about this later?"
However it seems that every time I do that, I find myself thanking myself for that cleanup several times over as the cleaned up bit repeatedly makes my life easier.
YMMV. In particular experience has given me a fairly good intuition about what kinds of changes are useful, and what aren't. (I don't try to make everything a gem! Conversely I've seen a lot of people spend a lot of energy on counter-productive "cleanup".) But these memories are why I continue cleaning things up.
