How many hours does an energizer battery can be in used?

It jus depends on a few factors like the capacity and how many amps the light draws n this n that. But I have found Energizer to be the best batteries for flashlights!!! With a single AA Energizer battery lasting anywhere from 2-5 hours with the flashlight being continuously on till it turned off. So they may even last a lil bit longer if not in constant use like that!!!