Pass XA 160 review:life span is 6 years?

In recent Stereophile review of Pass Xa 160 i remember reading that it's life span is 50000 hours.Does that means if in a near future i see a 6-7 year old Xa 160 for sale i should avoid it?What about those monster Krell amps that keep on working after 20+ years without being turned off?
What in this case is a life span of X250/350?Is it why there are so many X250/X350 amps for sale?I appreciate your replies.
Jmcgrogan2, you are correct, XA Pass series is pure class A. Conversely X.5 runs in class A/AB. There is a thread I started a little while ago that discusses the design/sonic features of the Pass X.5 series and compares them with the old Pass X series. See:
I will post there any new information I will acquire on these amps.
IMHO, once you go Class A there is no going back. That's probably why I prefer the sound of the older Krell/Threshold/Levinson/Pass amps. I thought the Aleph models sounded better than the X-series. I'll have to give the XA's a listen.
"I thought the Aleph models sounded better than the X-series. I'll have to give the XA's a listen"

XA is one notch above Aleph, it keeps all the good stuffs in Aleph but with better bass, image and treble. The difference is not trivia so that no A/B comparison is needed to appreciate the improvement.

"The XA series does run a higher Class A bias though, correct?"

No ! The total bias current is even higher but rail voltage is much lower.
The Pass Labs site has just posted an excellent comparison of XA160 vs X600 authored by Dr. Poltun, director of the archives at the Vienna State Opera. You will find it as a downloadable PDF file at the following URL:
Yeah - just so we're clear the issue is that for D dollars you can have W watts from XA series or 5 times that in X series (I'd have to open excel do find the actual numbers, and its probably not linear across the lineup. But that is the idea.). And the XA series dies out at 200W/8ohms while X series goes to 1000W/8ohms. So, another way of putting it, do you want the amp to sound somewhat better, or do you need super super megawatts? The XA series are considered some of the best amps that exist at all at any price.