I have an MX700 mouse that won't hold a charge more than a couple days, and Logitech tells me that its within spec and they won't replace it. Tried replacing the batteries and using another charger, same results. When I bought this thing six months ago, the first one was dead out of the box, and the second had a cursor that jumped all around the screen. I'm wondering how common a problem this is, I've run into a few others who have experienced much the same.