Leave it on?

@larryi  my tubes always seem to last longer when I leave the equipment on 24/7, tube filaments always seem to burn out quicker when I power them on and off daily.

I have a Pass Labs integrated, class AB, and they recommend leaving it on. There's a mute button but it doesn't appear to be a standby.  It still stays warm.

@mylogic Thanks for bringing up the environmental point. One things folks might do if they want to deal with energy costs to the planet is consider voluntary renewable choice programs, such as the ones offered by companies like Xcel Energy. Consumers can support renewable energy generation, thereby reducing their individual carbon footprint associated with electricity consumption without necessarily putting in solar panels, etc.

Invalid,

Your personal experience represents a small sample size.  Also, it sounds like you experience a lot of tube death in order to detect a pattern.  Is it possible that your gear is hard on tubes, particularly at turn on?  If your gear has tube rectification, turn on of the rest of your tubes will be inherently gentle.  Some tube gear have “soft start” circuits that slowly ramp up the juice.  
Almost all of my gear uses tube rectification.  I’ve been running the same amp and linestage and phonostage for 15 years and I have not replaced any tubes.  I cannot draw any conclusions from personal experience with that kind of data.

We use a Yamaha receiver for our TV sound and just leave it on all the time. It has been on for several years now with no issues. FWIW.