Leave tube amps always on?

Mark, the owner of Linear Tube Audio, suggested I leave my tube amps on all the time 24/7 if im listenting every day, and to turn them off if not using for a period of time, a few days or for example we go away.  His reasoning was that it uses considerable more energy to turn on/off on a regular basis. 

Do others agree?  Kinda risky since these NOS Mullard tubes ain't cheap and will soon be gone forever.   
Being an owner of ARC tube gear, my response is NO!  My gear is probably 80% of the way there after 20 to 30 minutes after start-up.  After an hour, my gear is all the way there.

I echo what another some of the posters said about tube life.  My amp uses KT-150s, which are expensive power tubes that, per ARC, have a service life of 3000 hours.  Too darn expensive to leave my gear running 24/7. 

I am also concerned about energy costs and even safety.

So, ... NO!!!    
I have a pair of Futterman OTL3s, modified from pentode to triode. 

If I’m listening and have to walk away for up to an hour or two, I leave them running. 

Otherwise, I turn them on, wait a half hour, and when I’m done, they go off. 

- fire hazard
- tube wear
- waste of electricity

The arguement for leaving tubes on is that they sound better fully warmed up not that the tubes consume excess power when you turn them on. Frequent on off tends to reduce tube life especially power output tubes. 

You should perform some experiments by listening to your LTA amp from a cold start vs fully warmed up. Can you hear a difference? What is the minimal acceptable warm up time? Please report back what you find.

Hi thx for the reply. Do you have an inconsistency in your first paragraph? In the first instance you said tubes don’t consume excess power when turned on, then you follow up with the constant turning on/off shortens tube life. Arent those two statements binary? Anyway, what you said is exactly what the engineer who built the amps said-- "frequent on /off tends to reduce tube life so leave them on"! That has the added benefit of keeping them warmed up all the time.

Leave NOS on 24/7? Nah. Heck no. It’s not about money. It’s about scarcity.

If you are listening for an extended period of time, e.g. all day, then yes. Power up in in the morning, then power down at the end of the day or weekend.

NOS are expensive and more importantly--scarce. If you decide to leave on for 24/7, then roll out the rare valves/tubes.

I have two separate systems, and they are in different rooms. One is valve/tubed and the other is sand/solid state. I save the better (valve/tube) system for extended listening. The cheaper sand system monoblocks running the high-end Martin Logans I use and abuse almost daily, because I don’t care about their longevity.

ML informed me that the polymer nylon diaphragm has a very limited lifespan of only 15 years. So, I don’t and can’t care that much. I can "care-less" :)