I have actually posted this myself a while back. Everyone who was kind enough to reply was split 50/50 on leaving on/off. I have even checked with manufacturers of some of my gear and got 50/50-LOL!
My system does double duty as an HT. I am only in my room Friday through Sunday. I do not use the rig Mon-Thurs. So what I just started doing is powering everything off (except my Furman Elite 20PPFI and my LHY SW6) Sunday night when I go to bed. This includes my subs. If the piece has a hard switch I turn it off. Then Thursday night I flip everything back on but I don't play anything. First thing when I get up on Friday AM before work I let my streamer play, volume low, until I get home on Friday so system is nice and ready for the hardcore listening.
Not sure if this is good or bad for longevity, but it made no sense to leave everything on for 4 days with no use. Fortunately for me I have a second system that I use mostly for tv watching during the week. If I was using the system every day I'd probably leave everything on...All manufacturers I checked with about my gear, have said it doesn't hurt either way to leave on or off...
Hope this helps...

