Most of the comments have been made already. I replaced most of the lights with these when we moved in 2001 and, as these start to burn out, am putting in the smaller, "warm", ones. (Don't believe the "lasts 7 years" stuff, BTW.) As Sorcha says, the original ones didn't fit into some fixtures, but I've had no problems with the newer ones. They may give out less than the alleged lumen equivalent, but I can replace 60w bulbs in the bathroom, for example, with 23w compacts, and get more lumens for less money. I've put a couple into ceiling fans as fan bulbs wear out, even though they aren't "rated" for fans, and have had no trouble.