I have a Qtronix mouse, that replaced the original A2000 mouse, still in use. The back-end pads wore off then the flat underside of the case started to wear away. The 'wear area' is like a "V" that runs back from the ball to halfway down each side. Now there is little of the front-end pads left.
I put on round nylon self-sticking pads at the back-end corners and cut these to half-height so the ball could make desk contact. After the front-end pads wear completely off I'll have to do the same for those.
Believe me, the corner-pads underneath a mouse ARE necessary! As long as those are replaced, a good mouse can last for a long- long- time!
I've found that a plastic placemat makes a good mousemat.