Can you do anything to make power tubes last longer ?

Balanced power supply. It provides exactly 120 volts at exactly 60 Hz...constantly.

IMO critically important to provide to tube amps...well, if you want your tube amp(s) to sound as it/they were designed to sound, which, sanity indicates you should. Oh, and bias holds better which increases tube performance and longevity,...huh, so I guess the more accurate sound is just a bonus to the longer tube life...funny how that works...

I'd never own an amp with cathode (auto) bias either.  

Also, I don't know what "regulate voltage" means, but I do know that the balanced power supply that I use makes exactly 120 volts.

Paper towels ftw

The designer and builder of our monoblocks uses the same Dodd Balanced Power Supply to power his builds that we use to supply power to our system. They makes exactly 120 volts at 60 Hz. The 75 lb. laminated core transformer takes whatever comes from the wall outlet and makes a +60v and a -60v rail, both at 60Hz, and then joins them at the outputs. The amps are optimized for KT77 output tubes and can run no other type of output tube. I foolishly tried all of the usual suspects, even though I was told by the designer/builder that it wouldn’t work; he was right, can’t get any other output tube type to bias correctly. Had a lot of Octets for sale for a while :).

Anyhoo, I feel very lucky about the amps being designed and built based on the same power supply; apparently, pretty darn optimal. Accordingly, I’ll say again, for tube amps, it’s worth using a Balanced Power Supply (or, I think, a power regenerator) to assure that your amp(s) see 120v at 60Hz.