While you may need a full eight hours of sleep each night to recharge, the batteries in your gadgets don’t. All they really require is a power nap. In fact, overcharging a battery will shorten its life, in some cases by as much as 50 percent, says Paul Klatt, a quality-assurance engineer at Batteries Plus, one of the largest U.S. battery suppliers. Constant charging generates heat, he explains, which is detrimental to battery life. As a general rule, you should unplug your MP3 player, cell phone, or digital camera when it’s fully charged and give your cordless phone a break from its base for a few hours each day.

You should also check to see what type of battery powers each device (this information can be found on the battery itself). Then follow these rules of thumb to keep them all in top condition.

Cell phones, laptops, and MP3 players usually use lithium-ion (Li-Ion) batteries. Charge these as often as you need to, whether they’re half-used or fully drained. But don’t fully charge a gadget before putting it away for a long time; store it partially used or you’ll shorten its life, says Klatt.

Digital cameras and laptops are usually powered by nickel-metal hydride (NiMH) batteries, as are some cordless phones. They can be charged as needed, but a monthly deep discharge (that is, draining them all the way) will prolong their life.

Power drills and cordless phones commonly use nickel-cadmium (NiCd) batteries. These should be fully discharged and then recharged. As with NiMH cells, this deep discharge helps the battery last longer between charges.