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.   
aj523
Tubes consume more power if turned on and off regularly so you should leave them on all the time? Clearly a flawed logic from the LTA owner 
Two years ago I asked Kevin Deal, Upscale Audio at the RMAF show (Denver) should you leave an integrated amp on 24/7 or only when needed.  His expression and definitive answer was "Only on when you use it!"All my integrated amp's tubes still sound good today.  I just occasionally clean their pins.  :-)    
This roundtable is entering the "How many angels can dance on the head of a pin" phase.
@hilde45 


Thats what I was thinking. How many electrical engineers with qualified expertise have actually weighed in here other than maybe atmas-sphere. 
@vinylfun

Sorry I dont know Kevin Deal. Is he an engineer ? What audio manufacturer  is he or / work for?