Many famous names such as Bach, Franck, Widor, and others have gone back and revised their organ works, leaving us with an example to follow.
When we're writing our own music therefore, and we find something important that we want to change in an earlier work, there's nothing wrong in principle with going back to make those improvements; a creative artist has every right to refine, even reshape, their work in any manner they see fit, any time they see fit; if something about it is really bothering them, then yes, they should go back and work with it, making those refinements until their heart is content.
This could take the form of correcting just one note or accidental to rewriting just one section to revamping the subject, countersubjects, and whole plan of a fugue.
If we're not very careful however, we can get bogged down in our pursuit of perfection to the point that nothing new is being created, studied, learned, or practiced because all of our time is being occupied with editing [See blog, Procrastination, Parts I, II, The Book, Part I].
We can forget that, at some point, every shoe is acceptably polished.
It's advisable therefore, once we're no longer feeling our way through part writing, once we aren't making frequent mistakes that beg to be corrected, and once we've passed through about 3 drafts of each, to attempt to leave our compositions the way they are and to move on to create new works and "ship" them (get them before the public) than to endlessly polish old ones [See blog, The Book, Part II].
Life is too short.
Perfection is a mirage.