The lights are on about 15 minutes total a night (a rough guess) and we've had them about one year. That's a little over 90 hours (365 times .4). We use them for indoor security checks in a large complex, so they are turned on and off a lot (let's hear it for the Mag switches!) The Mag thermal protection design works fine as the lights rarely have time to heat up and so for practical usage we get max brightness most of the time. One of the three did have the led separated from the metal base but the light itself had no obvious damage and the highest distance the lights should fall when dropped are waist high (our staff does not do any climbing or standing on high surfaces, at least I hope not.) The other two simply did not work. I've also got a 3 D for home use and I am happy with it's cost/battery life/brightness factors.
Sam44