Do you always keep the Amplifier powered on

If it's designed that way it's ok. The manual for my Portal Panache says it uses about the power of a 40 watt bulb, so ecologically your decision. sonically it sounds better and maybe even lasts longer according to many...

I turn everything off when I am not there.
Used to be a volunteer fireman, you see how easy a house can burn.

I'll share Schubert's POV.
It's only 15...20 for solid state to reach operating parameters and half-way down for tubes. Becides, if area is prone to surges, you're saving your equipment when not home.

I do not know exactly what electricity costs. But if it runs 1.00 a day to have an amp on all the time it adds up to about two hundred and fifty dollars a year you save if you only turn it on 6 hours a day. And that adds up to two thousand dollars in ten years which should be enough to have some caps and a power switch replaced. I think these figures might be quite conservative for an class a, ab, or a tube amp. And you will also be making a better world for the cute mice that live in the fields. Sounds like a win win win proposition.