That happens easily enough when you have multiple versions of the same file. What I do is keep the original as is (in my unfinished files folder), then label the succeeding variations b c d thus:
When I save as an mp3 (in my finished files folder), I erase the extraneous letter (b or c or d), so the last iteration I've worked on becomes my only finished file and the one I upload. Occasionally I find I preferred an earlier version, and I have it. Once the file is PL OK'd and the project is catalogued, I get rid of the earlier versions and just keep the good stuff.
That's just what I do, but some sort of filing system becomes important when working multiple projects at once and you find files scattered all over the place.