I keep two cubes of 30 standard alkaline AA in the basement, which I use as needed and replace when I get to one cube. The shelf life is five years if kept cool. The intended emergency use is a lantern, two-way radios, flashlights, FM/weather radio. I have never had a battery leak in storage, but I did have a leak in a little-used flashlight and a AAA powered remote once. Here is a link to some technical information: http://www.greenbatteries.com/batterymyths.html