An optical mouse relies on reflected light to tell it to move. Consequently, a mousing surface that is consistently colored will be much better than a surface with random colors. All a mousepad is giving you is your own consistently colored mousing surface.
I was at a customer in Virginia for the last three days, and my optical mouse worked fine on the desk they gave me to work at, but refused to do *anything* when I used it on a painted black metal surface that my laptop was on. Apparently that surface wasn't reflecting very well...
I also have an oak table that I have to use a mousepad on. It's lightly stained, and the grain lines in the oak are very distinct. Going from the very dark grain to the very light wood produces erratic results... not fun.
So when do you need to replace it? Whenever... [img]smile.gif[/img]
And I also scrape the gunk off the sliding pads every week or so. Usually when I'm on a boring conference call...
