Mine might be a bit less because I crank it to 1000 poll/s and play a lot of games. If you don't do any gaming and are fine with 125/s, you'll get a lot longer

Mine might be a bit less because I crank it to 1000 poll/s and play a lot of games. If you don't do any gaming and are fine with 125/s, you'll get a lot longer life. My last mouse that used one AAA lasts ~3 months on a battery.