stupid tube question of the day

As above tubes will burn out if left on. There are similar threads in the archives. Also please avail yourself to Audio Asylum Tube Asylum. A very knowledgable group of enthusiasts have addressed this issue.
That said I had a Jolida CD player with tube output. I rolled the Jolida tubes (Shuguang?) to NOS Mil Spec Mullards. The change was immense and worth the cost of the tubes. When the CD player gave up the ghost I retrieved the Mullards and tested them after a number of years in service. I didn't leave it on but played it often. I tested the tubes and much to surprise they very strong. So for whatever reason I have seen equipment that was not hard on the tubes. Could it be the design? Possibly I really don't know.
I hope this doesn't confuse you. All my other (a lot) tube gear I turned off or used up tubes listening.

turn the amp on and enjoy it, this is all pretty silly.

Another question: Any suggestions or guidelines on turning tube gear off when taking a listening break, and then back on again when the listening session resumes, if the break only lasts a couple of hours? The point of the question is predicated on the notion, perhaps wrong, that the process of turning tube gear off and an again -- by itself -- stresses and preliminarily ages tubes. Does the suggestion or recommendation change in the case of amplifier power tubes versus signal/audio tubes?? Thanks

"i run my tube amps 4 hours max. if i want to keep going, i turn them off for 30 minutes then back on.”

The seller of my premium tubes gave me very similar advise. I wish that I’d pressed for an explanation at the time, but I was suffering from sticker shock. Does anyone know?

I dug into the records and found that Alfred Kayser of KR Tube Products sold me my nos Mullards and advised me to not run the amp more than 4 hours at a time. That was over 3 years ago. Absolutely no issues with the tubes in that time. Also, the tubes I bought have almost doubled in price since then...