Leave it on?

I have a class A SS-Hybrid Pathos Inpol amp 

no way I am leaving vintage tubes on 24-7 and in Class A extra $$ for sure if left on 24-7 ,just turn it on when using within 15-20 minutes it sounds great !!

There are no absolutes. What someone else does with a different brand of equipment from yours should should have no bearing on what you do. Check with the manufacturer of your equipment and follow their advice.

You don't want to leave a class A amp on.  heat kills.  

Many amps now have a standby feature that keeps the circuit warmed up to the point that the designer thinks is appropriate and ready to go,

Jerry

There is no one size fits all answer. Some equipments turn themselves off after being inactive for a certain period of time (Marantz AV-10), others are just impractical (Class A amplifiers). On the other hand some can stay on and ready without causing any damage to themselves or the environment (Class D amplifiers, DACs etc). Some manufacturers recommend it. Just make sure the equipment is in dark mode (display off), otherwise you might cause display burn in where the characters stick to the display like a watermark even without power (not good for resale value). 

@spenav + 1