Quartz-halogen sources are characterized by a white light that renders objects lighted in their true, natural color. This is different from the yellow cast of standard incandescent light. Modern automotive headlamps (which operate at 12v) provide this type of white light, and it is even possible to identify an older vehicle at night by the color of the headlamps. The gases in the lamp envelope and the high operating temperature cause the tungsten which evaporates off the filament to re-deposit on the filament, thus extending lamp life; eventually, the filament will break, causing the lamp to fail.

Quartz-halogen lamps designed for 12v operation are generally long-lived. Lamp manufacturers publish lamp life data as "average lamp life". This figure is arrived at by burning a number of lamps continuously until half of them fail. Thus, if an array of 1000 identical lamps are simultaneously energized, the time elapsed until 500 lamps "burn out" is the manufacturer's "average lamp life". Note that the lamp manufacturers do not guarantee lamp life, they merely provide estimates of lamp longevity.