If you use cheap batteries, this mouse will suck the life out of them (and fast!), but if you put decent batteries in this mouse, it will last quite some time. I love the freedom of putting the mouse wherever I like, instead of being tethered to a cord. The only issue I have had so far (besides the battery thing) is that sometimes it doesn't work that well unless it is being used on a mousepad. It does work on pretty much any surface but it seems to "prefer" my mousepad LOL. Overall, a great little mouse.