I'm with Stevecham. Also if a amp manufacture is stating to keep a amp on all the time to sound their best, then it's a crutch and design flaw IMHO, I'd stay away. There are plenty of amps that sound great upon turn on.
Will leaving an amp powered-up all the time...
lead to "cap saturation" that causes the amp to sound bright? A friend sez yes. A listening buddy of his left his Spectral mono's on for three months and heard a difference when they had a normal warm-up.