Hello, this is my first post. Great forum. I am in my 40s (but well preserved). Took lesson through H.S., but never practiced. (When you and your friends are listening to Cream, Hendrix, the Beatles, etc. its hard to get pumped up about playing the Merry Widow Waltz). Got back into piano as an adult.
Anyway, something of interest: For years I have played the Moonlight Sonata 1st mvt. It is generally pretty good except for a few of those annoying "bumps" that always seem occur in the same places, and are tough to get rid of. I recently downloaded a new copy of the sheet music (same notes but a different transcription)...and played the piece from this much, much better! I think psychologically it got me away from some negative cues associated with the transcription from which I learned. Like "oh no I always screw up playing this part after turning the page", or seeing markings for trouble spots, etc." Has anyone experienced this? I proceeded to try it with Chopin's C#mi Waltz OP 64 # 2. Same thing...played it better.
Maybe it is just me, and others might find the opposite, that they need the "comfort" of their original piece of music.
Personally I think that it is great because just as I don't carry my piano with me, I don't carry my sheet music around either. So if I go to someones house, and they want me to play something on their piano and have some standard piano literature, I can feel very comfortable playing from their books.

Good point, or you can just memorize everything!