Why No Power Button on Some Phono Stages?


I am upgrading my phono stage, and several of the ones I have shortlisted do not have a power switch/on-off button.

Why is this? Is the user supposed to keep it powered up all the time, or manually unplug the power each time?

I know certain electronics are supposed to have better sound once they have reached thermal equilibrium, but that doesn't mean I want to keep it powered up 24/7.

Switching the phono stage power off from the power strip is a PIA, as it would switch all of my other components off, and I'd lose by tuner settings.

I want to choose the phono stage by sound quality, but an on/off switch is a major convenience factor for me. Why do some manufacturers leave it off?
kixo
The power supply for my turntable is the only thing in my system I leave on 24/7. My phonostage is a tube one, which I manually unplug every time. This is not at all unusual.
So, you want to choose a phono stage for sound quality, but you don't want to leave it on to get the best sound.
Thanks for all of your responses. Yes, I do seek sound quality, but I don't want to leave uneccessary devices on when I am out of the house for several days, often weeks at a time.

While I do agree that it's optimal to listen to components when they are at operating temperature, I would like the option of turning off a device easily when I choose to...
Post removed 
It takes substantially less play time than stand-by to worm-up. My area is vulnerable to devastating surges so my equipment is always OFF when not played. It takes one full album to play (near 40m) and wormup of Musical Fidelity XPS and pretty much the rest of system is complete. Do home errands while worm-up tunes are playing. They still sound great. I shut down my system or turn on with single button of Furman conditioner and care less about power switch on my phonostage.