Thanks for the suggestions. More info to see if this helps:
The sockets are rated for 60 watts each and yes, I admit sometimes sticking a 75 watt bulb in. My thinking is, “Hey, one of these is going to be dead soon, so I can use an extra 15 watts to compensate until I drag the ladder out to change the damn thing.”
The fixture is actually indoors, in the entryway leading from the garage to the kitchen. So it’s not outside and doesn’t get cold.
It’s about three feet from the door to the garage and 18 inches from the laundry room, which has bi-fold doors. We aren’t much for door slamming around here, but does just regular door closing stress the bulb enough to keep killing it?
I installed the fixture myself, but I’ve done that dozens of times and there wasn’t anything tricky about it.