Hey,
It boils down to this for me....I believe as an old Electrical engineer and technician for many, many moons...that most if not all equipment indeed need or should
come up to "stable" level to meet the circuits design...with vacuum tubes the chemistry in this old school tech certainly needed to come up to the temps required for proper operation
so thermionic emission could take place properly etc...with SS stuff the time for stuff to heat up to a chips designed temp is a lot less in most cases.
I myself turn on the Schitt dac I have and usually let it warm up for 10-30 min at most, more often than not just a few minutes and its sonic bliss for me for the most part.
But if one leaves their stuff on forever, well the benefit of that is when you indeed listen it certainly will be up to temp for sure. I wouldn't do this with tube stuff, just for a fire safety reason.
And with tubes turning things on and off can and will degrade stuff.
That said, I have 9 head amps and three dacs, cables from wire your win to silver litz cables for interconnects.
Sources are several PC's all with Win 10.
I use USB, Spidf and coax. I went thru a listening session several weeks ago with a very good CD transport using its optical coax out vs Spidf and compared to USB both 3.0 and Schitts latest gen 5 ....quite an eye opener in itself.
Amps I have are the Schitt Asgard, Lyr, Vahalla 2 for the moment, Bottlehead Crack w/speedball, (2) O2's with mods, an ODA which is a DIY AGDR design of what the O2 desktop was going to be with 3x more current available than the O2, several DIY amps with TI's latest chips designed just for audio head amps OPA 1688's ...and three AVR's.
My headphones are now mostly Beyer's. Been thru dozens from Grado, AKG, Audio Technic, Audeze, but settled for now with T90's, T1's and DT1350's.
Dacs are HRT Tech MSii+, Several ODACS, Schitt Bimby.
If your hearing a difference that's great but for the most part except for the difference in headphones, the only real world differences that have made me say , OMG was the addition of the Bimby...which leads me into other questions....and this is with it...
Its a grand hobby isn't it?
Alex