I no longer carry chemical lights for all the reasons posted previously. Changed to a CMG Infinity ($18) and prefer it. Much longer and brighter light. Much more practical and easier to maintain. I know it will work, cause I can test it. I frequently leave it on all night like a night light when I am sleeping in a unfamilar location. Hate to bang and thrash around in the dark at night. I usually change the battery (rechargable NiMh) after about 3 days. Never let it go to see how long it will run. Hmmmm.... I will do that over the next several nights and see how it goes... report to follow...