We've already explained how excessive heat can take its toll on battery life. But your recharging habits can screw things up as well. According to Battery University, each recharge cycle wears down a battery by a small degree, and it's smarter to partially discharge a battery rather than drain it dry. In fact, the only time you should fully discharge a battery is to prevent the dreaded memory effect on a nickel-based pack, or to calibrate a smart battery.
Apple says that for accurate reporting of an iPad battery's charge, you should run at least one charge cycle per month: Charge the battery to 100% and discharge it completely. Oh, and one more tip from Battery University: Turn off your tablet while charging it. The "parasite load" of the device can affect its ability to detect a full charge, and possibly overcharge the battery or cause mini-cycles.