OK, ok. The deal with Lithium ion batteries is that preferably you don't want to always drain it out completely, maybe at 3/5 of the way at most usually. The scenario when fully discharging would really be needed is when its charge meter somehow goes slightly off, which might happen noticeably maybe after a month of frequent full recharges. The explanation escapes me, but I assume it has to do with the electrical circuits. Unlike old nickel batteries, there isn't really a problem with frequent short recharges.
Modern laptop batteries should have built-in electrical circuits to prevent havoc from happening when the battery drains out. That is, when the charge hits a certain level, the circuit would retain it to a fair extent. Not exactly sure how long it gives you, but leaving it uncharged for say two years is not really a good idea anyway. For some reason keeping the charge at ~40% is ideal for storage.
Keep in mind that if you leave the battery in, it could discharge by a noticeable amount in a few weeks even when the laptop is off the entire time.
Also, you don't really need to bother with fully discharging/recharging. The battery meter should have been correctly calibrated in the factory in first place, unless shit happened.
Finally, what really hurts batteries is heat. Leaving the battery in while the laptop is plugged technically should not cause damage, as it won't overcharge. Except running a laptop while plugged means more power can be used, potentially generating more heat. But this mostly depends on the power options set.
