One thing that can make a big difference is if you are "touching" the glass bulb with your bare hands. I ALWAYS wear rubber gloves when replacing anything electrical and also use some dielectric grease on the snap in part. Other than that, you could be having a short somewhere.
This could also be down to a bad battery as some owners have solved their issues..
The big sleeper in persistent headlight failure is engine mounts. They harden and the vibration gets to the headlight filaments. Try setting a plastic cup of water on the radiator cross-member when the engine is running and compare the amount of ripples to a similar car.
When I worked in avionics I went to an autopilot school, and they told us of an autopilot a customer had brought in because it was porpoising (constantly pitching up and down) and nobody could fix it.They finally tracked it down to hardened mounts on one of the engines; the vibration was driving the artificial horizon gyro nuts.
Fingers touched the bulb glass during installation – the small grease deposits cause hot spots
Fuses protect circuits from overload so I guess it is not that.
Hi at a guess faulty body work rust and poor connections.