New homeowner here. So far, in less than a month, three burnt out light bulbs have just slid out of the sockets, leaving behind the threaded metal part. I know about the potato trick, but there's no broken glass left behind. I found this question
that seems to describe my problem, and tried this solution
(didn't work, although it seemed promising at first), and I've already broken two fixtures trying to get these bulbs out (sigh).
At this point, I'm less concerned about how to fix what's already happened, and more interested in WHY it's happening so that I can keep it from happening again. It may be noteworthy that once I can get the metal part to twist out, a powder comes out (like a corroded battery). Is it the wiring? The fixtures (the house is about 30 years old, and the two fixtures I've had problems with (so far) seem to be original or nearly so)? Just old bulbs? Would it help to change them all right now?