I work at NAPA Auto Parts during college and the Lazer blue head lights are a popular commodity. Unfortunatelly, people are buying them because they look cool, and they want to immitate the real HID Xenon which is simply absurd. There's several things about new bulbs that some people need to know.
Halogen bulbs are usually the typical equipment in our automobiles and snowmobiles. If you want to upgrade to a brighter, whiter bulb, get the "Brite Lite" version which contains Xenon gas rather than Halogen. These work! I use them in my car and in my snowmobile and they are slightly brighter. These are a good replacement type for average vehicles.
Now, the new thing we all see on the roads is blue headlights everywhere. Why? It originated from what many brand new European sports sedans come with from the factory as an option. These are known as HID lights (high intensity discharge) or some call them HID Xenon. These head lamps do NOT have a filament like a typical bulb does. The light arc is created between two electrodes. The bulb is filled with a mixture of noble gases as well as Xenon gas.
So what's so good about them?
The HID's put out nearly 300% more light than a halogen bulb, while only using HALF the power in watts. HID's only use about 35W and yet they put out the brightest light on the roads today. (with the exception of aircraft lights) You can see farther and brighter.
The problem is that most auto manufacturer's can only implement the HID headlights in the design of NEW cars. I see alot of "wannabees" on the road who would like to have HID lamps, but you cannot just buy the bulb and install it. You need to replace the entire headlight assembly to get true HID's which is VERY expensive! Anywhere from $800-2000 dollars.
There is a high demand for the look, so light bulb manufacturer's have sort of "immitated" the HID's by producing bulbs with a blue coating on them. And, of course, they put them on thier new Xenon gas bulbs so that they can claim to be "brighter" than halogen yet still get the cool blue color. This is where the confusion lies.
Blue-coated Xenon gas bulbs are brighter than typical halogen, BUT, they are not brighter than the CLEAR Xenon gas bulbs. The blue coating fades some of the light. If you want brighter replacement lights, please, buy the clear Xenon bulbs, they are brighter than the blue ones.
If you want the true brightness of the HID Xenon headlamps, such as those found on new BMW, Audi, Mercedes Benz, and Porsche, than the only way to get that is to buy the entire headlamp assembly from performance shops and dealers........which is NOT cheap!!!
I'm already despised at seeing these 10 year old trucks drive by with ugly faded blue lights that you can hardly see out of. It's just silly, and the real kicker is that they are usually less bright than what they started with.
I hope this clears things up.
-oh yeah, and to answer your question, the regular Xenon gas bulbs will last just as long as any Halogen bulb. It's just a different mixture of gases to help newly designed filaments burn brighter. The only real thing that shortens their life span is either breaking it, or touching the glass with our oily fingers.