I almost forgot that one of the reasons that I bought this particular trackball (Logitech's Optical Marble Mouse) is that it's left-right symmetric. (Physically, that is, not functionally.) But my right shoulder was a bit mouse-fatigued so I switched sides. I'm just a hair less in control than when right-handed, but a small price for ergonomic help. Besides there are interesting tiny differences in the way you think about mousing lefty. Navigating submenus seems to be the least fluent part. Been a few days as a south-paw now and I should remember to do this more often. My shoulders feel much better today.

I used to always switch every so often when I was a full-time mouser, but for a while I had a right-handed trackball (the oh-so-great, but asymmetric Cordless Trackman Wheel, which is wireless) and forgot about it for a long time. My only complaint with this model is that it has a cord. A cord! Bah. And, actually, they could have put a bit more effort into the substitute wheel mechanism (the up/down scroll buttons are never as quick as I want them to be, no do they do any acceleration). Ahem. So this trackball could be better, and I'm sure there are better ones to get, but the day I bought this I was impatient and it's plenty good enough for now. Still, much better than mice, ergonomically speaking. (I'm surprised so many people use mice and I'm surprised people put up with Qwerty keyboards. Topics for another day.)

(I just wish PowerBooks still had trackballs instead of trackpads. The march of progress…)