Your mechanic has the retardism. Connect a multimeter to the leads for each lamp, one at a time, and activate the lights to determine if one is fucky. Check for voltage and current. Filament-based lights also blow out if they're frequently exposed to drastic temperature changes, like being turned on and off, heating and cooling. This stress will eventually break the filament, which is why incandescent bulbs blow out as they're being turned on, but almost never if they're constantly on. 

 Not my job 

 They're halogens so I think they're overheating quickly 

 Enjoy being ticketed by zogbots every twenty days or so, then. 

 I've been driving for 5 years and haven't been even pulled around a weigh station. I turned my hi beams on and I'll replace it when I get back today