The set that came with my mouse probably lasted 2 months, and I had a non-alkaline set of batteries last like a month and a half after that. Now I am using the extra NiMH rechargable batteries I have for my digital camera and each charge is lasting about a month. Definately a lot better option than wasting new batteries. $17 for a charger and something like $8 for a set of four batteries is a good investment.
I have my mouse on the same mousepad I've had for a couple years, because of the gel wrist rest
it's a light gray
when the first set of batteries died, I didnt know it til the message window popped up and told me to change
the second set didnt give me a message window, my mouse pointer just started tweakin and freakin out, I put some of my NiMH batteries in and it was better..put the old ones back in to check and yep it tweaked again
and so far with the NiMH batteries, the mouse just pretty much stops responding
I usually have my reciever on the floor (because it insists on falling down and it usually works fine on the floor anyways) but the other day my mouse was being a little unresponsive so i put it back up and my mouse is workin fine.
Oh yeah I guess its important to mention I don't have the mouseware software installed now, which would be why it doesnt tell me when the batteries are low.
And to answer your question about taking the batteries out, Testlacoiled... I just leave them in all the time, with rechargeables I'm not gonna go to the effort of taking them out. And here is logitech's info on the light when the mouse is idle.
How does Logitech help me get the most out of batteries?
Cordless MouseMan Optical works in every possible way to maximize battery life. The cordless mouse spends its time switching between sleep and awake modes. The optical sensor has four different levels of brightness that indicate which mode it is in:
Bright - Mouse is in full run mode. LED is flashed 1500 times a second.
Glow - Mouse is on but dimmer. LED is flashed 100 times a second.
Strobe - Mouse is in sleep mode. LED is flashed 10 times per second.
Flash - Mouse is at lowest response level. LED is flashed twice every second.
Whenever the user moves the mouse or clicks a mouse button, the mouse instantaneously returns to full run mode.