I try to never leave my headlights on when I turn the car on or off... There are too many voltage fluctuations during those second or two that could cause headlight burnouts. It's also the reason why many of the accessory systems shut down when you're cranking the engine (radio, blower fan, etc). Besides, the voltage fluctuations, you want to supply as much battery power to the starter motor as possible.In reply about this thread, my suggestion to close it still stands. It's not because there's no useful info here. It's because there is too much info about too many things. It's turning into a "shout box - part duex" thread. There are currently 253 posts in this thread and probably 100 of that is about the original topic, another 100 used for arguing and another 50 about other subjects. I didn't count but I doubt I'm too far off.