Can you leave cordless drill/driver plugged in for long extended periods?

I would like to buy a cordless drill/driver but would not be using on a regular basis (well... most of the time... infrequently). Would that do damage to the rechargeable batteries? Would it be better to only charge prior to when I know I will be needing to use it?
Any insight would be helpful. Thxs.
6 answers 6