When do you turn off the tubes?


Having had recent surgery and spending a lot of time at home, I was wondering how long a break from music do you feel you need to be taking before turning off your tube amplifier.I could leave it on all day even when not listening but that would be 12+hours/day.While my PrimaLuna Dialogue HP is gentle on tubes, the thought of retubing 8 KT150s is an expensive prospect.I usually turn the amplifier off if I am not going to listen for around 3 hours.What do other people do?

crwindy
Mine are on most of the time. I was told it was start up that caused most issues and a larger percentage of tube wear? 
I have a tube DAC and Pre with SS amp. 
Everything gets shut down if I take a break of more than an hour or so, or if I leave the house.

I’m in same camp
Many tube amps have a stand-by mode in which the output tubes are off but the amp is still warm. My Cary amp have this. When I'm home and know I will be listening that day they stay in standby. When I leave the house or go to bed, everything gets turned off.
I once saw my tube preamp go up in smoke while it was just idling.
I usually shut the amps off each time I am done listening.  Whenever I leave them on thinking I am going to go back to listening, my day usually changes so I can't.  If I turn them off, the odds of being able to listen more dramatically increases.  And, these things get hot-- including heating up the room when you have 8 kt120's per amp x 2, a couple of m8080's and a 6922 in the preamp, and the Sophia's in the CD power supply.  24 tubes total when everything is on-- that's too much electricity to waste if it's not in use.  And, finally, I have seen a tube fail-- right in my amp-- spectacular but scary.  I want to be around if/when that happens.