But mice have always annoyed me (we'll stick to the physical aspects here). As the years passed, I seemed to more frequently have problems with my mouse-arm and wrist tensing up and aching.

Then about 3 years ago for the first time an episode crossed the boundary between ache and pain. OMG!! Do I have CTS after so many years of typing and mousing??? Anyway, I went to my chiropractor who "broke" the muscle-tension "logjam" in my upper body; I was feeling nearly symptom-free the next day. So at least it wasn't likely to be CTS (whew). But I was motivated to try mouse-substitutes in a quest to prevent this from becoming a chronic problem.

Shortly thereafter I bought a cheap (20 USD) Logitech Optical "Marble Mouse" (really a trackball). Since switching to this device, I've experienced ZERO arm or wrist discomfort! The need for a tightly controlling grip on the mouse is gone. The physical stress of "mousing" is GONE! Every PC in my home, and my PC at work, is now equipped with one of these devices.

The only feature I miss on a vs. "real" mouse is the wheel-scroll 'button' on a "wheel mouse" (which can be mimiced using the Logitech driver; since I eschew multiple-mouse-button-click (chording) features, I simply haven't tried whatever workaround Logitech might offer).

Regardless, I'm a completely happy user of this arm/wrist-saving device. Check out the reviews of this trackball on Amazon; you'll see that my results are the norm. And thus far, these devices are remarkably robust: I've had zero failures in approx 8 mouse-years of use.

For $20US what do you have to lose?