Years ago I repeatedly developed carpel tunnel swelling in my right hand. I switched the mouse to my left hand and that solved the problem. I think keyboarding plus mouse-clicking plus using my right hand for writing all built up too much strain. Switching to my left hand for mousing distributed the work, and I have not had a problem since.

At night, I use my laptop keyboard, so I have to become right-handed again. This means twice each day, changing my mouse settings from for the left and right buttons.

A little hotkey utility called SwapMouseButtons solves this problem. This would be good for anyone who switches mouse hands or for a house with right and left-handers who like to move the mouse from one side to another.

It even has an option to make your pointers mirror so they tilt left or right, reminding you which way the mouse is set.