Originally Posted By: eljefino
You have halogen bulbs which should be as bright as they were new, until they conk out.
Not true at all!
Halogen encourages the tungsten vapor to re-condense onto the tungsten filament instead of condensing on and coating the glass; which both extends the life of the filament and reduces the dimming due to age... After many hours and many on/off cycles halogen bulbs are nowhere near as bright as the first day they are installed (though they retain much more brightness than an equally used sealed beam).
Originally Posted By: Sylvania Website
...By providing up to 50% greater brightness*...Because headlights dim over time, by as much as 20%...
*Compared to worn standard halogen
According to Sylvania's published specs their "Standard" 9006 bulb outputs 1,000 lumens and has a 1,000 hour lifespan. Their "50% brighter" bulb referenced above outputs 1,000 lumens and has a 300 hour lifespan.
I quickly searched for 912 lumens and found Phillips 912 bulbs are rated at 1,875 lumens and 1,000 hour lifespan. Probably illegal, and potentially dangerous for oncoming traffic. I say if the lenses and reflectors aren't clouded or otherwise damaged throw in a pair of new standard bulbs. I can almost guarantee you will notice they are brighter.