I got one of these today in the mail. I got it on a big sale. It seems to be performing well. My question is about the power. I saw a You Tube video that said this mouse can go to sleep, to save power. I see nothing on the Logitech site about this. Does anyone know? I don't expect my battery to last for 18 months, because I use my computer more than a lot of people do. I was using a Microsoft wireless mouse, but it started acting up. (it was for laptop use anyway) The thumb ball takes a little getting used to. I have an old Logitech wired trackball, I used the heck out of it, but it doesn't work good anymore. I cleaned both the old Logitech, and the newer Microsoft mouse, but neither performed right anymore. So, I decided to get this new trackball by Logitech. I don't want to wear out the battery more than necessary. So if this does sleep, it would be awesome. Please drop a line about it, if you know about this.