You do realize that all tubes are aging during every minute that you are using them, do you not? So, you can pay hundreds or thousands of dollars for tubes that may sound wonderful on day one. That is a best case scenario, because in many cases inexpensive tubes will sound better than these rare NOS tubes that cost a great deal of money. But let’s assume that The expensive tube does sound great. From that moment forward it is decaying. Eventually your investment will fizzle out. You can get much more bang for the buck, if you learn how to solder, and how to read a schematic, and upgrade coupling capacitors for example in your gear. That sort of change is permanent and never goes away. Capacitors make a far larger difference to overall sound quality than do tubes.
Furthermore, when you do pay big bucks for a tube and install it, you are then very biased toward hearing an improvement. None of us is free from that listener bias. You have spent the money, so it must’ve done a lot of good. Get your wife or someone who doesn’t know what you did to have a listen, before you get wild over a boutique vacuum tube.