That's one of the reasons, yes. I'd like to preserve my hand because I'm a musician who plays three instruments and any sort of wrist injury wouldn't be good. The second reason is desk space. I'm currently using a mouse with only about one stretched-out hand's length of desk area.

I "tried out" trackballs a couple times at computer stores a long time ago and I remember even simple tasks being quite difficult. So back to my original question, how long did it take any of you trackball users to switch over from mouse and be back at the top of your game?