I just replaced the battery in my 15" Macbook Pro. After a bit more than a year's use, the battery's performance had degraded to the point that it wouldn't last more than 45 minutes on a full charge. My usage pattern for the battery was to leave the laptop plugged into mains power except when away from an outlet, and to recharge as soon as possible when I got back to an outlet, no matter how little of the charge I'd used -- my logic was that since Li-Ion cells have a limited number of charge cycles, I'd better charge it as rarely as possible. Obviously, this didn't work out the way I planned. In probably 90% of days, I'm tethered to a desk at home or at work. Some days I'll use the machine on an airplane flight, at a conference where no outlets are available, etc, but this is relatively rare. So I now have a Crap Battery and a Good Battery. I'm willing to switch between the two as necessary to prolong the life of the good battery. Any advice on what pattern of use will keep the good battery shiny and long-lived as long as possible?