MRC I don't really understand the difference between enharmonic equivalents on an instrument like the piano (on cello, which I play, yes). But since I'm not a professional or even a particularly advanced pianist, I think about it from a more pragmatic point of view: if the way a piece is notated is hindering my being able to play it, then I have to make some changes, or at least allow myself to "cheat" by writing in enharmonic equivalents. I certainly know and can follow the modulations and see why it's set up the way it is, but, I just want to play the piece with the least amount of friction possible!