As far as I know, this opinion is unique to me, and I think there’s a good chance that some people might find it a little wacky. But here goes: Every time I see a driver get out of their car and walk away, leaving the headlights on, I think, “I could never do that“.
Yes, I guess it’s a little crazy. These days most cars have some sort of electronic mechanism that automatically turns off the headlights a few minutes after the engine is turned off or the car is in park. Sometimes I watch, and, sure enough, I see that’s what happens.
Bur suppose the lights don’t go off by themselves? If that happens, the car’s owner might return to a car with a dead battery. That’s a chance I don’t want to take. Sure, the car lights go off by themselves more than 99% of the time … but there’s going to be that one time when it wasn’t a good idea to act as if you believe that no automotive component could ever fail! Nothing in a car ever just stops working!
Besides the risk of the lights staying on and draining the battery, there are a few other things that come to mind.
Could leaving the headlights on mean that they will burn out sooner? It stands to reason that any sort of headlight is only going to last so long, that is, some certain number of hours of “on” time. If you burn your headlights an extra few minutes every time you start the car, they’re going to reach the end of their useful life sooner.
Also, using the headlights needlessly wastes gasoline. The electricity in a (gasoline-powered internal-combustion-engine kind of) car’s battery doesn’t just come out of the air. The electricity is generated by the car’s alternator, which is turned by the engine. When it’s actually making electricity, it’s a little harder to turn, and therefore the engine uses a little more gasoline whenever the alternator needs to make electricity to charge the batter or operate the car’s electrical components. Not only does burning the headlights for no reason waste gasoline, it also adds wear and tear on the alternator and battery, shortening their lives.