Tube Preamps Should Have This Feature

"casual listening for a short time"

Your system is going to sound darn good 2 minutes after you turn it on. Try it. Play something favorite, involving I bet. Wait 30 minutes, play again. How much ’More’ involving?

The practice of waiting 20, 30 minutes, (I do it) we convince ourselves, for me it’s why not, but I go cold often enough? Someone coming over, oh helllll yes, warm it up!!!!!!!!!!!

@dweller 

I think that you're worrying way too much about tube wear. Life is short; just use it and be happy.

Agree that life’s too short to stress about such things, especially with regard to a preamp where tubes tend to last pretty long and are relatively cheap to replace.  Music soothes the soul even if it’s just for 30 minutes, so just do it!

The Freya is an excellent choice and does solve this problem. I have one and primarily listen to the buffered, solid state stage for a couple reasons. I will disagree with @elliottbnewcombjr and say that the tube state does not reach its potential for 20-30 minutes, and is nothing special until then. Mine is on all of the time, and occasionally I listen to the tubes, but not often due to the warmup requirements.

I am in search of a new preamp and have trialed a couple solid state designs. I am not opposed to tubes, but would like one that I could just leave on all the time that would not burn through a lot of tubes, and also would not heat my house. Are there tube preamps that you can just leave on all the time and expect to get reasonable tube life?

Find something else to worry about!

How do I know when my tubes need replacing?

Power tubes like EL34's and KT88's are good for about 2500 hours or more. But may go longer in an amplifier with a conservative design. Small signal tubes with numbers like 12AX7, 12AU7, and 6922, and rectifier tubes like 5AR4 may go 10,000 hours. So you get years and years of enjoyment. Using a tube tester may or may not tell you if you need a replacement. The best approach is to buy a new set of tubes, and install them. If they don't sound a lot better, put in the old ones and suck every bit of life out of them.