Any danger to letting a MacBook stay on the charger long-term? I came into possession of a 2009 13" MacBook Pro. Most of the time, it will be used as a desktop computer - but there will be instances when I will need the 5 hour battery.

Is there any danger to letting the machine stay on AC for weeks at a time? Will it kill the battery, or does the Macbook have a charge/discharge routine?
Ideally you should let your computer discharge completely every month to avoid losing battery capacity.

Apple has a calendar to remind discharging the computer every month at webcal://www.apple.com/batteries/images/notebook_icalreminder.ics