Hey gang, Bought a wireless Mighty Mouse a few weeks ago from someone on Craigslist. Connected it and it's been working great. The battery life said that it was full, however, all of a sudden, it's down to two bars. From those of you with experience with the battery cycle, does it the meter remain full until it's running out and all of a sudden drop out or is it a bit more gradual? Also, what have you found the typical battery life is? Is it better to keep the mouse on all the time or to switch it off when not in use. Just wondering about switching the power on and off and if it actually uses up more power doing that then just leaving it on. Thanks!