Hey, I wanted to share an experience with a couple of light fixtures in my house growing up. Both fixtures were installed before I was born and took bare incandescent candelabra bulbs. One was above a bathroom vanity and took 5 bulbs. The other was a foyer chandelier and took 12. In the 19 years I lived in the house, probably only about half the bulbs in the chandelier were replaced. I know because they often stayed burned out for years since it was really hard to get to. I attribute the long life of this fixture to voltage drop. The fixture hung with lamp cord and a chain, plus there were four 3-way/4-way switches in the (big) room. I imagine voltage the the lamps may have been around 105.
The bathroom one only had 2 or 3 of the 5 bulbs replaced, and all were when I was really little. I attribute the long life to the fact the the fixture was on a rotary dimmer that had to be twisted to turn the light on, so power was gradually ramped up over a second or so, preventing thermal shock. I remember thinking about putting one in every room to make the bulbs last forever.
I remember climbing up there when I got older and looking at the filaments, I was astonished. The finiments were sagging! Not just dropping a little bit, but SAGGING. There was a black spot on the top of each lamp, and if I set the dimmer to minimum brightness, you could see "hot-spots" on the filament glowing much brighter. All signs they should have been EOL. Several years after this "inspection", they were still running fine! Idk about the sagging though, does this happen with old age or high power cycles? Some of the filament segments would be almost dropping straight down from the supports. I don't have a picture sadly.
The house was renovated, and I came home one day to find the fixtures outside by the dumpster with all the bulbs shattered. So I never got to do a final inspection on them.
Also, is there a time period when they decreased the number of filament supports have 3 to 1?
