This mouse is flawed because it doesn't go to sleep after a period of inactivity like my optical cordless mouse does. This means that if you forget to turn it off on the bottom of the mouse (a hassle) or don't return it to the recharge base before retiring for the night-in the morning the mouse will be nearly dead and will require a recharge before you can use your computer. A word to the wise.If it went to sleep automatically, you would not have this problem. Since I wanted a laser mouse for more precise movement over an optical one, I'm keeping my MX400 cordless optical mouse for now as it does go to sleep automatically.