Batteries naturally lose some capacity over time, but I have no idea what I can do to preserve as much battery capacity as possible, aside from periodically recalibrating the battery. Is it best to always have it plugged in and full? Will running it off of battery shorten the life? Does it shorten battery life if I run my MBP on battery for a few minutes and then recharge, or should I always aim to run the battery to empty before recharging?