Thought I was just burning out bulbs in my passing lights, until I checked the last removed bulb, hooked a 10 Amp battery charger. The used bulb didn't look burned out, but it would not light up. Thinking there was a loose connection in the base of the H3 55 bulb, I gave it a whack, and it sparked inside. I gave it a few more whacks, and both filament wires broke clean off inside the bulb.
Closer investigation revealed that the filament wire had broken off right next to the glass base of the bulb. It appears that the bigger, heavier filament of the 55 W bulbs cause the filament wires to break off due to the vibration and road bumps.
I have gone back to the cooler-burning, less power-sucking, H3 35 Watt bulbs. Maybe these will last longer between replacements? It's like the H3 bulbs are not built to handle the stresses of vibration on a bike? Does anyone know of a better bulb type that will work better?