If you've got a netbook with really great battery life, you'll probably still have loads of time left even with only 10% of the battery remaining. Here's how to tweak the settings so it alerts you or goes into sleep mode at a more reasonable time.
Note: obviously if you don?t have a great battery in your laptop, you should probably be careful with these settings or you might lose data. If anything, you?d be better off making the notifications happen sooner in that case