Fistful, what I know about wiring I learned from my father and from my late father-in-law. I don't know diagrams, but I've run a lot of wire, conduit and BX in my time. Never had a problem, but sorry I can't help you with yours.
Desertdog, all three bulbs were from the same package. I'm suspecting the package was part of a defective batch.
Just to be sure, I've put in a bulb of a different wattage that we've had in the storage closet for months.
Again, just to be clear, when I put the new bulbs in and hit the switch, everything was fine. It was only the next day, when flipping the switch to "on," that the bulbs burned out.
There are a lot of things plugged into that circuit, most more fragile than a tungsten filament. I'd imagine a voltage surge would knock out any circuit board in an appliance before it would a 60-watt filament.
And, as long as I'm posting about this, am I the only one who thinks that the quality of light bulbs has gone downhill? Sorry if this seems trivial, but the threads on the bulbs now seem so coarse that it requires extra agility to get them screwed in.
Tomorrow's exciting thread: "Is toilet paper of lesser quality than years ago, or am I just eating too much pizza?"