I use a Wacom tablet. Many people think its because I'm a designer/photographer and it is super duper handy for those types of programs. But the main reason is ergonomics and all my wrist pains disappeared once I made the switch a decade ago. Even if I'm surfing the internet, or working in an excel doc I still try to use the pen and tablet as an input device- it's just much more natural. I believe the mouse or trackpad and most variations are unhealthy.
And try signing your signature with a trackball
It is hard enough with a mouse. For me, it is impossible with a trackball.