How long can I expect my 15" PB to stay asleep? I never shut down my PowerBook, I always put it to sleep by shutting the lid. It can be a couple of days between uses. I was wondering how long I can expect it to stay in sleep mode before running the battery down. I don't really want to lose the state. I may use it at work, bring it home and leave it in the bag and forget to charge it. If the battery level gets too low, when in sleep, will it safely shut down? I do make a habit of saving all files before sleeping.