I currently have 3 mice (all different shapes), a trackpad, and a trackball hooked up to my workstation, with some on the left of my keyboard and some on the right. I switch between them depending on what currently hurts most. Seems to work better for my tendonitis than when I only used one device with my right hand. It's basically all the devices I went through, one at a time, trying to figure out which worked the best. They all do!
Changing it up is really important for certain. In fact ergonomic advice for dealing with carpal tunnel syndrome is going to contradict advice for dealing with ulnar tunnel syndrome.
I currently have 3 mice (all different shapes), a trackpad, and a trackball hooked up to my workstation, with some on the left of my keyboard and some on the right. I switch between them depending on what currently hurts most. Seems to work better for my tendonitis than when I only used one device with my right hand. It's basically all the devices I went through, one at a time, trying to figure out which worked the best. They all do!