I just got a wireless Mighty Mouse, and despite the complaints on this forum I personally think it's a great mouse. The only thing is that I'm not too keen on constantly turning it on and off and then having to go into the bluetooth menu to re-sync the mouse. I had an old wireless mouse that I never turned off and it ran fine. Is this the same of the mighty mouse? If I leave it on and connected to the computer but completely unattended, or if I close the lid of my MacBook without shutting off the mouse, will I still only have to change batteries like once a month or so? Or will that suck the life out of the batteries?