Originally Posted by 2000 C280 Sport
LOL. Same here. Our 91 Le Maquis Corvette and 95 GMC SUV dont blow out as many bulbs. Funny how that is.
I cannot remember how my W210 did but from the cars after that (W211, another W211, W221, W204 and a W212) I've changed one bulb (one of the bulbs at the trunk had failed before the car was delivered). We have to use lights (including low beams) day and night! The cars from 211 onwards have LEDs and HiP bulbs which may make a difference (and Xenon headlights).
I've followed a few Toyotas (probably a model that is not sold in the US) that blow head light bulbs every 5000 km, they even made Toyota specific bulbs that run longer.
If the cars use the same bulb brand/model, the main thing about bulb life is the supply voltage. At a lower voltage the lifetime is extended significantly. The compromise is with light intensity!
The difference in bulb supply voltage may come from the alternator regulator but often also wiring to the head lights is made cheap and makes the voltage drop (not enough to make the wire hot but enough to make a noticeable difference in bulb life and light intensity). Wiring is more of an issue for head lights that draw a lot of current (although the wires are smaller for the other bulbs).
In addition to the supply voltage, the bulb holder can make a difference. If the filament gets stressed by physical movements, it fails sooner. This might be one source for bulb life issues (note that bulbs like those of the W211 HiPs at the rear lights are directly soldered to the rear light circuit board to keep the bulb steady and to avoid contact issues).
Quite interesting to observe a completely opposite experience between different cars and owners.