It depends on how much you will use it. With NiCad batteries, you need to use them all the time. Run them dead and then recharge them right away. With me, I might go 6mo to a yr and not use the drill. When I get it out, the batteries are dead and won't hold a charge. So, I went with LithIon in my Hitachi drill. They hold their charge, don't develop a memory, and recharge in about 1/2 hr. So, like I said, it all depends.