Connie- You should run the battery down in that the battery is RECHARGEABLE and recharges whenever you plug in the laptop. So you are NOT wearing it out by letting it run down--you are giving it a longer life. It is best to unplug the laptop when you have it turned off also. That will help to run down the battery a bit. The thing with the rechargeable batteries is that they "learn" so if you never use them they will lose their charge but if you run them down (just like a phone battery) then they will take a full charge the next time you plug in the computer. The battery isn't to keep a backup when the computer is off--that is a different battery--not the one that powers the laptop when it is unplugged. Joan In a message dated 1/16/2009 1:53:24 P.M. Eastern Standard Time, [email protected] writes: I vaguely remember the only batteries to let run down were phone batteries.? I never use my lap top without it being plugged in.? The battery is to keep back up for when the machine is off or for short uses.? They are too expensive to run down completely.? That is just my take on it.? Connie