A few years ago I read a book by a medical doctor who said that using a mouse as little as 6 hours a week can cause problems. I decided to minimize my use of a mouse.

For example, to open a file, I hit Alt - f - o. (one after another, no need to hold anything down.) My right hand doesn't drag a mouse onto a little word on the screen, my left skips lightly up the keyboard.

Other combos:

to print   alt f p or ctrl p
to save alt f s   or ctrl s
to close alt f c
to exit alt f x
to highlight a whole document ctrl a
to find ctrl f

The more things you can do without a mouse, the better!