Wow callibrating my MBP battery improved my MBP battery life by 45 minutes to an hour. I was only getting around 3 hours of battery life on a full charge initially and now I get around 3:45 to 4 hours. At least that's what the indicator says. Too bad this machine is going back. I'm still waiting for a return shipping label from Apple as they are sending me a new machine due to a logic board error. I've had about a week to play with this one though and it's like being on crack!!!