SureFire has posted nothing definitive that I know of (unlike Pelican who rates most of their lamps at 30 hours) on their expected lamp life. That said, I've gone through more than 15 sets of batteries (1 12B, 1 12BB, and a few 2 packs) and am still on the same lamp. It's survived drops onto carpet, concrete and asphalt and is still holding up. If you total it all up and assume I changed the batteries after 65 minutes, rather than the spec'd 75 minutes, you come up with 18.75 hours thus far and it's still running nice and white.