I have three headlamps and two very reliable small flashlights that I keep either with me or nearby at all times. It's common for my job to lose power in a storm, or sometimes even high winds. Emergency lights at the perimeter of the walls aren't nearly enough. Having my own light works a lot better.

I've bought all my head lamps on the cheap, so they're not light cannons, nor are the headbands the best. But they do. My last two were purchased at a home improvement store for under $5 for the pair.