Leave preamp on all day, off at night

Turning tubes on and off helps the tubes last longer. That's simply a fact. Tubes don't age when they're off.

wolf_garcia"Turning tubes on and off helps the tubes last longer. That's simply a fact. Tubes don't age when they're off."

Wow that is an amazing fact you have stated that tubes don't age when their off what a remarkable conclusion you have arrived at however you're other "fact" is no fact at all because turning tubes on and off does in fact cause them to age and this is the reason for leaving many tube products in the "on" state. Again we see wolf garcia is one of he contributors here who sees his pronouncements and determinations to be some infallible and unchallengeable expressions of truth when in fact it is pretty obvious that you are one of this group's second or third grade American "grammar school"
 children.

Turning tubes on and off helps the tubes last longer.

I believe this is particularly true at turn on when you do what I used to do with my tube amps.
That is, I bring the heaters (filaments) on first, so the plates and everything warms up, then with a delay circuit after 1 min I switch the high tension on.
The reason was because NOS RCA Black Plate 805 tubes were very expensive if you could find them.
And of course tubes don’t age when they’re off, wolf was just having a dig!
Cheers George

Clearly the answer for tube longevity is to never turn a tube amp on at all...this does have an impact on the sound of your rig as there will be none, but the tubes will last MUCH longer.

@divesh and others, this may help shed some light on the subject.

May I present Exhibit "A"

"Getting the most out of Vacuum Tubes," by Robert B. Tomer

http://www.nutshellhifi.com/library/MostVacuumTubes.pdf

The topic begins at the bottom of p. 96 and the answer can be found on p. 99

You can download an read the book at your leisure.

I believe the key factors are the design and mfg’s estimated life expectancy of the tube.

If a manufacture states that a tube has a life expectancy of say 10,000 hrs., then a tube that is on 24/7
will obviously not last very long. There is approximately 8,760 hrs in one year.

Using the above as an example:

Given a life expectancy of 10,000 hrs. - 8,760 (1 year) = 1,240 hrs. of useful use remaining.

There are other factors obviously that will contribute to the useful life of a given vacuum tube.

So, there is probably no definitive answer. It will depend on the tube, usage, etc.

It’s a damned if you do and damned if you don’t kind of scenario.