Would you buy a tube amp if you were unable to use vintage tubes in it ?

Fifteen years for the amp and linestage and the tubes that were put in those two components were old to begin with--they tested good, but prior usage was unknown.  Both components run the tubes very gently.

I also run tubes in a headphone amp and a phono stage.  I would have also recorded no tube failures in these two components as well, except a shelf collapsed onto the power supply of the phono stage and wrecked both rectifiers.  This is a very odd phono stage-Viva Fono- that utilizes two 300B tubes as rectifiers.  So, this was not a cheap replacement caused by that shelf failure.

faustuss

 Further I think all the suggestions regarding tube "rolling" is a little insane . . . What a crock!

I nearly spit out my coffee when I read that comment.  LOL. Another flat-earther's credibility shot to hell.

- - - - 

The best location for my JJ 12AU7's in the storage closet.

I would have some doubts about any such extreme longevity unless the tubes are run VERY gently.  There are some people who claim their table radio has been left on constantly for decades so it might be true that some tubes can last for a very long time.  The particular Western Electric tubes I run have lasted very long for me as well as for a number of other people who have bought similar gear made by Aldo D'Urso, an Italian builder who is very much into Western Electric gear.  

How long a tube lasts, it believe, is primarily that of tube design.

So for instance a 6550 tube will typically have a ~3,000 hour life.

On the other hand a 300B will have an expected live of 40,000 hours.

Many small tubes share very long life. 

I just recently learned about the 300B. I decided to get my self a backup set of Takatsuki 300B tubes (Japanese) in case their price went up considerably because of tarrifs. At $2K for the pair, a sizable increase in price would be a lot of money. Then I looked up the average life... 40,000 hours. Maybe I didn’t need the backup set... I’m over 70. Oh well. 

Secondary factors are how "hard" they are run in the design and if power tubes, how hard the amp is run (as in how high is the volume).