Lithium-powered flashlights are typically smaller and lighter than rechargeables. When lithium batteries are used up, you replace them. Unlike rechargeable batteries, lithium batteries do not self-discharge. In fact, SureFire lithium batteries have a 10 year shelf life; a lithium-powered flashlight placed in a drawer will function a decade later. This is why many police officers carry a lithium-powered light as a backup to their main rechargeable light.

Because of their small size, lithium-powered lights are a good choice for camping and hiking, personal defense and daily carry. And their 10 year shelf life qualifies them as great backup lights in the event of a disaster.

Rechargeable flashlights make sense if you use your flashlight for at least a few minutes each week. Rechargeable flashlights may cost a bit more initially but, depending on usage, they can save you as much as $75 a year in battery costs.

SureFire rechargeable batteries can be recharged up to 1,000 times, never develop a memory and each rechargeable light includes an extra battery and a SmartCharge recharger. The downside is that, for a given light output, they are slightly heavier and larger than lithium-powered lights, require regular recharging, and necessitate a recharging device.

Rechargeable batteries self-discharge, so don't think you can grab a rechargeable flashlight that was last charged four months ago and expect it to be fully juiced. Just like your cell phone, if you don't keep it topped up with a fresh charge, it will slowly drain itself. This is the inherent nature of all ni-cad batteries.