1 headlight lasts 3 yrs the othere goes out yearly????

I've had the same sealed beam in the left side for almost 3 years now but have had to replace the right side twice now. The bright works fine but the low beam is gone.
I plan to upgrade to h4s soon but for now I'd just like to replace the sealed beam and it actually last.
What gives? Why does the right keep dying?

Not sure, but I'd bet that there are more potholes on the right side of the roads, and more vibration and hard shocks from that.

Another random guess - wiring harness comes from the left side of the engine bay, the wires to the right bulb are longer, lowering the voltage supplied to the bulb. Quartz Halogen bulbs apparently sometimes don't like this:

wikipedia said:

With a reduced voltage the evaporation is lower and there may be too much halogen, which can lead to abnormal failure. At much lower voltages, the bulb temperature may be too low to support the halogen cycle, but by this time the evaporation rate is too low for the bulb to blacken significantly.

Click to expand...

EDIT: these are a few guesses... they make sense to me but I don't guarantee that they're correct

Poor connection on the affected side's headlamp pigtail?

Just order a set of Autopals for 40 buck and get a good bulb for them.

Switch the left and right bulbs...

Could be poor quality replacement bulbs just failing faster than the original. The expensive Silverstars I tried in another vehicle only made it 4 months each. Check that the headlight housing isn't rattling either.

I second getting the AutoPal e-code housings and some H4 bulbs. Make or buy a nice relay harness and you can run brighter bulbs too. I've got generic Napa house brand 80/100s ($11 each) in the Autopal housings. They seem to last about 18 months, the low beams have a nice sharp cutoff, high beams are awesome, and I never get flashed by oncoming traffic.