Calibrating the battery prevents the adaptor from overcharging (or undercharging, but that's not so much of a problem) the cells.
Not quite. The point of calibrating the battery is to ensure the time estimate in your menu bar is as accurate as possible. The charging system is designed to disconnect the battery from the charging supply once it has reached a certain voltage level.
Also, two of the biggest enemies of lithium ion batteries are heat and time. Your battery will lose capacity over time, from the moment of manufacture, regardless of whether or not you use it. I still contend leaving your adapter plugged in as much as possible isn't the best thing to do, if only because you're not getting your money's worth. I mean, what's the point of having a notebook with wires attached to it most of the time?
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