Question regarding pre-amp and amp

I keep my amps and pre amp on all the time. I was told by a designer that keeping them on all the time does less damage than the on off cycle. By keeping on the caps and resistors maintain temperature and when pushed by more volume they are already warm. By turning on and off you create a heating and cooling cycle or expansion and contraction. That expansion and contraction can cause cracks that lead to failure. We have been told for years that excess heat is the evil in electrical components. To some degree it is but the heat cool cycle takes the evil to the next step. Example I have my old Sansui 7070 running in my wife’s salon other than power outages it has not been shut off for 25 years and is running strong.
Keep them on and enjoy the music.

The sequence of always turning on the preamp first and turning it off last seems to preclude using the trigger feature.  I have mine set up to trigger through preamp, so the preamp turns on and then triggers the amp on, and when I shut it off the preamp turns off and then triggers the amp to turn off.  

Always leaving both on seems like it would shorten their life instead of extending it, wouldn’t you think?

@sgreg1 having a tube preamp, I don’t think it will be a good idea to leave it on. With the solid state I never turned it off until now and now I am having to do it because of tube.

@bob540 how did you achieve the triggering?

My tube pre amp the Freya + allows for me to turn the tube stage off while keeping the pre amp on and that is the procedure I follow.

@sgreg1, I know there are multiple like that. But not my preamp. It’s a very good preamp and wanted to see what options I might have.