My Mini is a 2005 S that has the xenon lows beams and halogen high beams. Do either of these bulbs get "tired" and become not as bright! My low beams seem to be really, really white with good light spread. But the high beams cast the old halogen yellowish color. I am sure these have never been changed or replaced.
Thanks all!

 

I think your question is whether either type of bulb steadily degrades over time and whether bulbs need to be replaced even if they haven't failed yet. The answer is no.

Really not so different from a standard bulb in your home (excluding fluorescent bulbs). If you see an obvious change, a bulb may be starting to fail but otherwise the light is normally stable through the bulb's life.

Those are the normal colors for those types of bulbs. There are aftermarket halogen bulbs that are slightly brighter or produce a whiter color, but don't expect them to match the xenons.

 

Ditto, you won't find a true match, there are JDM type bulbs out there that are advertised to be color matched, but these are just tinted bulbs that not only diminish the output of the bulb and the coating just ends up burning off & then the tend to be even yellower & dimmer than a normal bulb. (this may even be what you have)

Your best bet for high beams is just a pair of Sylvania Silver Stars, they'll stay white & give you good visibility.

 

Xenon's are fine till shortly before death...then s light purplish color shift.
Halogens DO DIM with age...
This is VERY apparent if you have DRL's turned on....the DRL's run the halogens at a lower wattage...running a bit cooler....
over time, while running like this DOES lengthen their life, it DOES make them yellow faster...
The 2005+ Xenons are so good I find I almost NEVER use my highbeams!! Having installed 3M headlight lens covers/protectors within a few days of delivery has kept the lenses PERFECTLY clear...heck the covers are still nearly perfect..best $$ I ever spent for my car...wish my wifes car had them (non-MINI)...I have to polish them regualy..and they are still kinda yellowing with age.

 

Yes they do. All headlight halogen bulbs degrade over time. The degradation is generally slow and will often progress at a higher rate as the bulb gets older. As with any maintenance item, bulb degradation is affected by driving habit and initial quality and construction of the bulb. It is often recommended that headlight bulbs be replaced in intervals of two to three years
If you doubt it, put a new one in on one side and see how much brighter it is.

 

Xenons... what ZippyNH says. The only difference is the brand and when they were manufactured. I just changed out my Xenons on my BMW 523i here in Germany. The old Philips 85122s were a little on the bluer side, while the Maxlux 4300Ks are practically white.

As for the high beams, if you are not happy with their brightness, you can opt to swap them out for a set of Xenons (with ballasts), or you can put in something a little higher in wattage. I installed Osram 64217s, which are 65W bulbs vs 55W OEMs. It's about an 18% difference. Don't go any higher. You will either burn out the factory relays, melt the housings from heat, or both.

 

The Osram 64217's are the solution to better lights at night if you run halogen lights. Huge difference...stock bulb lumens is around 1600, the Osrams are 2100...you will see the difference.