I play with one band that tunes down a half step and one in standard tuning. We are not tuning down to sound heavy, it's to bring the tunes into the singer's range while the guitar can continue to use open string voicings. I usually play a 5 string (Sadowsky Vintage 5), so I could just transpose, but I would like to play in the same positions as the guitarist if I can. I'd like to use the same bass for both bands, so I tune down for one rehearsal/gig and up for the next. The neck is quite stable and it's only a half step, so it all feels OK. Other than the fact that it's a pain to constantly retune, am I asking for trouble with the instrument by doing this all the time?