Hi. Yesterday I had a very atractive offer that I cannot decline. Someone offered me a Microsoft Memory Mobile Mouse 8000 for a little price as $1 buck, the mouse tough, doesn't came with any accesories, just the mice. Well, I tested it and it worked ok (I used its Bluetooth interface). Since this mouse uses one AAA battery I took one of my TV control, I don't recall when I buy those batteries but they're duracell. The mouse functioned OK till a couple of minutes ago when the battery runs out, I must admit that I keep the PC on for a long time (15 hrs aprox.), but I feel the battery ran out too fast (I think the battery was too old). This is my first wireless mouse, so I wanna know the average lifespan of a mice's battery?? THX for the advices.