GM cars and trucks come with many types of lights right from the factory, but headlights are probably the commonest. Headlights are of two kinds. Low-beam headlighting brightens the way well enough in most driving and weather conditions. High-beam headlighting shines wider than low beams. This means you can see better in darker environments when no other traffic is coming. Many headlights also function as hazard lights, better known as flashers. These warn drivers around you of problems or dangerous situations on the road nearby. They can also signal that you're in distress. Some GM vehicles have headlights that also feature fog lights. Those brighten your way better in bad weather, shining low at the same time to minimize glare. OEM GM headlights feature one of three types of lamps. One, the most common, is halogen. Another is Xenon, also known as high-intensity discharge (HID). The last is LED. The headlights your vehicle needs depend on its body style, but when to replace any car light bulb depends on its type. Xenon headlights should be changed when they weaken, or about every three years. Replace LED headlights if they or their electronics die. Change halogen headlights every couple years at least. The best headlights for the project are genuine GM. You can order them right here online at our auto parts counter, along with the light assembly kits you need for installation. Buy today and save money and time!