75K mile checkkup on my 2007 Subaru Forester, they discovered a burned out parking light. When it was replaced neither low beam headlight worked and both were replaced @ about $50 each. Seemed like a remarkable coincidence for both to burn out at same time, especially since one had been replaced 6 mos ago. Could replacing the parking light bulb mess up the headlights?

I’d be suprised if replacing the parking light bulb did anything to the headlights, more commonly you get a little bit of oil from your skin on the glass of the bulb that causes it to burn out.