At night or when its realy dark like bad over cast
You must have two headlights, all other lights are in fact not headlights and just additional light aids.
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.
You would not drive it at night or when the law says you must display headlights.
5PM to 6AM
Headlights
Generally 30 mins before sunset
30 minutes before sunset
When visibility is 300ft
Just at sundown, or in fog and rain.
in florida you must dim your headlights from the oncoming traffic at 500 feet. and from the rear at 300 feet.
2!
Generally 30 mins before sunset