4000 hours my eye! After buying a 10-pack of these bulbs, I put in several in a set of downlighters on three bars in our kitchen-diner, which is only on when we have breakfast or dinner, so at most 3-4 hours a day. 11 days later one of them not only went, but short-circuited and so blew the fuse serving the kitchen and the hall, the first time anything like this has happened since we fitted those lights in 2008. I see that four people who've written reviews about these bulbs not in the 10-pack but singly - and which I wish I'd read before I bought! - have found these bulbs popping in no time at all. It seems downright irresponsible of Amazon to carry on selling them regardless. I only give the bulb one star because there's no option to rate it zero.