Should Class A Amps be left on??

Ok- Audiogon members need some advice here. Should Solid State Class A Amps be powered all the time? Have heard two school of thoughts on this. Apparently from what I have heard this is a moot question for Class A/B amps due to the usual low biasing of A/B Amps. From what I have been to learn so far Class A Amps should be left continously on.