Do you always keep the Amplifier powered on

A dealer I trust said it takes 24 hours for solid-state to reach its peak (1-2 hours for tubes).
If you listen every day I'd leave it on (not class-A however). If you listen only on weekends, turn it on Friday morning for Sat-Sun (connected to surge control of course).

Electricity in my area costs about $0.006 per kWh. For 40W it would be $0.0576 daily = $21 per year. My amplifier (total idle power = 10W) that costs me $5/year doesn't even have power switch. No power switch on my Benchmark DAC1 (also 10W) or Apple express as well. All is plugged into Furman power conditioner, including DVR set to record shows. Unplugging all three individually doesn't appeal to me. Furman has strong non-sacrificial under/overvoltage protection but I still unplug it during thunderstorms.

"Electricity in my area costs about $0.006 per kWh."

Where do you live?? National average is $0.18/kwh!! Mine is $0.25!

I have an old Sumo Nine, Pure Class A unit, that has never been turned off... except. I took it out of the system for about 4 months while I used Abletec Mono amps (Class D)... My Electric bill went down about $20 a month!... Now they are both in and I'm bi amping. I don't turn them off. Either amp, even though fully burned in takes a lot of hours before it settles in completely.

Kijanki, are you using solar battery or individual windplant?
My bill is averaging $.11/kwh
Dweller, you may continue to trust your dealer, but the fact is quite different in reality.