Yes and no. It’s good to let it stay on for some time if it’s used sporadically, but a periodic off/on cycle is good as it helps “clear its head” if you will.
I guess some want to keep it warm. Whether it helps on class AB and under is up for debate it seems.
A small house. One that isn’t inner city or LA/San Fran anyhow
As a former Harman fan, I’m really not sure that makes the “audiophile” tier. It’s pretty solid and precise sound wise, but not exactly lively (logic 7 d**ital excluded from my experience)