There is a light bulb in Livermore California that has been burning since 1901. The Shelby Electric Company made the bulb. It was hand blown and then outfitted with a carbon filament. It has about 4 watts of light.
The fire department claims that the bulb is at least 108 years old and has only been turned off a handful of times. If that is true, your looking at approx 946,080 hours of run time
FYI, the 2nd longest running bulb is in Fort Worth, Texas. Its been there since September 21, 1908.