Modern day computer mice are built to last, with the analog balls of yesteryear all but extinct, and fancy new lasers most computer mice tend to last a long time.
If you spend a little bit more on a slightly nicer mouse, they tend to last even longer.
The problem I had with my Razer Diamond back is that it's nice rubberised button coatings was wearing thin, and the silicone sides were yellowing.
Solution? Sugru of course!
I made two basic modifications to my mouse, the main one being to cover the main two mouse buttons with Sugru, custom moulded to my finger tips. The second, to replace the yellowed silicone down the side of my mouse.
When I mentioned what I was doing, The Ideanator pricked up his ears and took note, and in the time it took me to write up this instructable he had already added some modifications onto his mouse, and got some pictures. So you will see a few shots throughout of his project, and how he did his compared to mine.