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?
A Solid State phono preamp sounds far better when left on all the time. On our Liberty B2B-1 I decided to put a power switch on the back of the unit should one decide to turn it off between listening sessions, it draws only about 25W when powered up. I recommend leaving it on 24/7 for best sound quality.

On our BIG Olympia Preamplifiers and Phono Stages there is no power switch they are designed to be left on 24/7.

In my own system I leave the front end's on 24/7 while turning of the power amps when not in use.

My favorite story on this subject was a gentleman from the San Francisco area whom bought a set of our Whitney amplifiers sometime in the late 90's. In 2008/9 he was visiting someone down here in San Diego and asked if he could bring them by for a check up. He brought them by on a Saturday and I gave them a check over and they measured / performed like the day they left our shop. The guy had never turned off these amps in 12 + years other than the occasional power outage.

Good Listening

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...
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