HID’s don’t like being cycled quickly, so it will shorten their life but by how much I’m not sure. Assuming it’s the 2011 in your signature, have the bulbs ever been replaced in it?
Nothing in the service records. That is why I'm nervous. I know the ballasts can go too.
If you use them a lot, I’d get them changed. As HID’s age, they get dimmer. Philips rates their standard HID’s at B3/Tc=1500/2500. B3 is where 3% of lamps have failed, Tc is 63.2% have failed. That being said, many people only change them when they fail completely, I can’t blame them for it.
From personal experience, I swapped my Durango’s (at the time) 3 years old factory HID’s for new ones. The old bulbs were supposed to be 4200k in color, and they were actually bluer than my new 5500k Osram CBI’s! Not to mention the new bulbs were significantly brighter.