reply to cdru
Re: Headlight output degradadation over time? Yeah, vibration may have an effect, though I think in normal use its effect is probably negligible in properly designed and installed bulbs.
Can't speak for any other vehicles, but in my Bronco, over 13 years and 150k+ miles, I never had to replace any light bulb other than license plate light, in spite of that a good portion of those miles were night, or off-road driving,
Wacky Races 2012!