How long do the bulbs last?
The tungsten filament in the halogen bulb can and does burn out.
HID’s do not have a tungsten filament like that of a halogen bulb.
Since HID’s do not have a tungsten filament they can last up to 3000 hours as opposed to a halogen bulb which can last between 450 – 1000 hours.
The reality is that both types bulbs can and often do technically last longer providing that there is a stable power supply (meaning your electrics are good!) and also how often they are used.