I prefer to think in terms of time - not percent. 3% is pretty low in my book. I never let mine get below 10%. Basically, I like to have about 15 minutes of life left for graceful shutdown, etc. At what percent that is - who knows. That depends on what you are running. If you are playing a movie in the DVD drive full screen with sound, it doesn't take long to use up 3%. Another tactic is to always carry a spare, fully charged battery.