Tube reliability in amps


I am contemplating the purchase of a tube power amp. I already have an Audible Illusions pre-amp, which has given me virtually no problems tube wise. I would like to hear from a bunch of Audiogoners on how long power amp tubes last in the real world, do I have to keep matched pairs or sets around or can I just replace one? Also I have B&W matrix 804's and I have been told tube amps are not a match for them or that I need a lot of power (read expensive tube amp). Wavering between tube and SS, HELP.

PS. I listen to orchestral music and piano. Sometimes loud like about 90 db.

Thanks
drjjpdc
to blues man and the few last posters, I am not an audio novice. It's just that I am a tube novice. I know listening is top priority. It's just that I am not a tweaker. I don't want a lot of down time due to finicky tubes, long warm-ups etc. My listening time is limited as it is. To use an analogy from the the world of cars and bikes, I never understood all the tweaking that the early Harleys or British bikes and cars required. Seemed their owners spent more time fiddling with them than actually driving them. Have the same fear with tube power amps.
I have had great success with the Music Reference RM 9 MK II
amplifier. I have had EL34's in there for years already, and I still have no problems with noise or sonics. This amp
creates a good argument for tube reliablity.
I've been very happy with CJ tube amps for reliabilty, sound, and ease of tube replacement and rebiasing. I'm running the CJ Premier 11a as it does a fine job with my Thiel CS 1.5's. I'm not familiar with your B&W's and if they are in fact "difficult to drive" then you might want more power and that usually equates to higher cost. (not talking about low power SET amps here as they do not apply in this situation).
Ive been using a pair of VTL monos that have easily adjustable bias (about 30 min 2x per year and it could be done a lot quicker but i'm kind of a-r about it). Warm-up time is usually about 30-45 minutes before they start sounding real good, they keep getting better for the next hour or so...they sound somewhat dry and one dimensional at first...kind of like solid state. I bought them 6 mo old about 2.5 yrs ago and am still on the original tubes excepting 2 a near hit lightning strike claimed. They will probably need to be changed out by summer end (getting a tad soft but still sound good). I also use tube guitar amps exclusively and they live a MUCH harder life than any audio rig...no problems there so far either. try the tubes you won't be sorry