Quoted: I guess I should have asked it this way: do headlights ever fade and get dimmer, or do they just burn out completely? |
The bulbs do get dimmer as they get older, but they usually burn out by then...thsi was pretty common with sealed beams. More than likely is the lense gets cloudy, tinted or scratched as it gets old...this was actually one of the US DOT's arguments for keeping sealed beams as the only approved lamp back in the early early 80s. The reflector too ages and stops working as well as it did when new.
When changing out the bulbs, since you're in there might as well change both bulbs.
mm