I have a MBP 13" (Mid-2010) and I've read several different opinions on keeping the battery in the best condition. Many suggest that even with the unibody MBP to calibrate the battery by discharging it the whole way and re-charging it. I typically keep mine plugged in and have only used 51 cycles in 2 years and mine says 88%. Is there any proof that keeping it plugged in with the unibody MBPs has a detrimental effect on the battery life? Should I stop leaving the power plugged in 24/7? If you calibrate your unibody MBP then how often do you do this?