HID bulbs go bad over time?
 

Too the 993t out last night jsut to burn off some spider webs and smog is coming up. I have never driven it at night since I bought it. The lights on it seem bright enough in the garage, but out in the open, it isn't nearly as bright as my Cayman or any of the newer cars (I know, I know, 20 years newer tech). I only winder if new bulbs will perform better due to old age of the original bulbs? Its has 23,000 miles on it, so I cann only assume its original. Will they get dimmer like Halogen? What if its isn't used much? Tell you this, I love the Cayman S lights and how they turn with the steering imput.

That's my understanding. I have them in my Touareg and had to replace one. They told me you are supposed to replace both at the same time and I said BS. They are now a different color and brightness.
Go figure.

I'll second that. My Mini has HIDs but just wasn't lighting up the road like I thought it should. Got a pair of new xenon bulbs, and the difference in brightness between the original (13 years old) and new bulb side by side was very noticeable. I don't plan on keeping this car forever so just went with semi-no name brand bulbs, seem to work just fine. Keep the old OEM ones as spares!

Exactly the case for my GTI. But the new bulb is less bright. They're too expensive to replace both.

I have to check, but they are around 60-80 a piece for Osram or Phillips. I flipped on my high beams, they are almost none existing. I Have to remove the headlight housing to look, but the high beam sucked big time. I am also wondering if its halogen or xenon bulbs. Not sure if they are different or makes a different in light output.

You can use Panasonic Lumix lenses on a Leica SLR2, but people will laugh at you.......

Yes. They get pink tinted and dim at the end of their lifetime. Amount of miles does not mean a lot. Their lifetime is limited by number of starts and number oh hours.

If one is going, other will be soon. So replace both at the same time.

If your high beams are halogen, recommend Osram Night Breakers.

4 years and counting on my replacing one and not the other. But, that's surely the kiss of death for it.

2007 Ford van, OEM headlights were so bad I seriously wondered how they could have been legal. I converted to HID's and immediately had a ballast fail, no problem on the replacement being sent by the vendor but what a PIA to replace, just a tough area to work on. They were certainly an improvement as I wouldn't even drive at night with the originals. Now, two years later the drivers side is INOP and I can't wait to troubleshoot and have to find replacement parts...

Might check wrecked-em yards to see if Mustang HID parts would fit. My '09 Mustang has factory HID's...actually, I was a bit disappointed...think the H-1's on my old 911S were better lights.