It depends alot on what you're playing, also. The vibration feature must drain it quite quickly. After about 30'ish hours of gameplay my stock batteries died out. There was, of course, a noticeable drop in the energy bar after getting into reel fishing in Zelda. I've have a pair of batteries I rotate between my personal 360 controller and Wii-mote, and they've lasted me a decent time. If anything, I think they drain slowler on the Wii compared to my 360, but I'll have to play a bit more to see that.