What could cause 3 headlights and numerous tail lights and license plate lights to burn out within a year. No fuses have blown and no other electrical problems.
It is most likely due to excessive voltage from the alternator. The DC voltage should not exceed 14.8 volts while the engine is running around 2,000 RPM. Check the AC ripple across the battery also. It should not be more than .1 volts AC.
This would be a problem with the alternator.