according to Canadian driving instruction , from dusk to dawn , & if you don't have day runners that come on when vehicle starts , then it's at all times .
In Illinois they must also be on whenever the windshield wipers are on.
5PM to 6AM
Due to law changes headlights technically are allowed on at all times even during the day and MUST be on in the evening when it starts to get dark
You must have two headlights, all other lights are in fact not headlights and just additional light aids.
185 metres
Headlights are used during times in which it may be hard to see. In most states, headlights must be used when driving from dusk before sunset to sunrise.
Headlights are required to be on from sunset to sunrise, and any time the visibility is less than 1000 feet.
you must use your headlights between one-half hour after sunset to one-half hour before sunrise, or anytime when person or vehicles cannot be seen
Motor Vehicle law states that headlights MUST be used after sunset. IN some states they must be used all of the time, when it's raining or snowing or when conditions require it. If you have an accident because you choose not to use your headlights, your insurance company will probably not pay anything for it.
it's an illegal to use a different colored headlights.
You would not drive it at night or when the law says you must display headlights.
use low beam lights within 300ft of on coming vehicles
Headlights should not be left on while the vehicle is not in use. If you are not driving, you will just drain your battery while having your headlights on.