rule of thumb: how long do you leave a tube preamp on versus turning it off then back on?

I have had the exact same thoughts as you, OP.  I read through the posts and didn't feel anyone actually addressed your question.  If I am hearing you correctly, this is the scenario.

You have had your stereo on for whatever amount of time listening and your family wants to watch a 1 hour show, so you have to decide.....do I leave everything on and go watch the show and then come back and hit play or do I power it all down and then power back up an hour later.  

Which is harder on the tubes, an hour of idle time or the power cycle?  

I understand the incentive for sound quality, but I too don't know which is harder on the tubes regarding their life.  

It seems that many electronic components in our lives are more stable when left on constantly vs repeated power cycles.  

Seems we are both over-thinking and should just leave it on for reasonable amounts of idle time.

Yes, thank you for reframing my exact question! I think no one may actually know the answer because there are too many variables for a "rule of thumb" guideline. Lots of well intentioned responses. I'm going to turn it on a little before or concurrent with my listening, and leave it on the rest of the day, turn it off when I head to bed. Done! I'm over it!! Thanks!

@wokeuptobose


Don’t know if this has been covered. But NEVER turn a piece of tube equipment off and back on quickly. This is one of the best way to cause problems with the equip. .
You having already owned tube amp, may have already known that. But just in case....

Thank you for reminding me! I have known that most damage to electronics is caused by the cycling of being turned on and off. I will be doing power cord and interconnect shootouts and I'll be sure to be careful not to cycle it on and off. I used to leave all my solid state gear on all the time, but a few years back we had a voltage surge and it damaged my Wadia 16, three TVs, two sound bars and several other electronic items. Now I'm careful about turning my system off each night. I did install a Leviton whole house surge protector at my panel and I do have everything but my SS monoblocks plugged into a Shunyata Hydra Delta 6 which theoretically has surge protection, but factory claims about "FULL" protection are unclear to me.