It will last longer than any of us, with occasional new tubes and very occasional replacement of electrolytic caps, like every 20 years. With heavy use a switch or potentiometer or tube socket might eventually need cleaning or replacement. But basically a unit like that has an indefinite lifespan. People still use Marantz and McIntosh preamps (and other brands) sold in the 1950s.
Herron VTPH-2A discontinued
I came across a post recently http://www.vpiforum.com/viewtopic.php?f=7&t=19187
and confirmed it through the Herron website. Bummer.
and confirmed it through the Herron website. Bummer.