There’s so much real expertise here, I’ll only add one thing about my own situation — If I find a way to test my outlet and see that it is noisy, I plan to make it dedicated (if price is reasonable). Why? Couple reasons.
One, as MillerC. said (at some point, maybe not here), one can learn to listen with more attention and acuity; a better line creates good conditions in which one can hear more. If one doesn’t do that — because they can’t hear a difference *now* -- then one has blocked that path of growth.
Second, I’ve gone to some trouble already to deal with power — a conditioner, good speaker wire, power cables for my gear, etc. I’ve not gone crazy but I’ve not stuck with stock cords. That approach — not to accept any lowest-common-denominator elements in my system — seems logical to extend to the breaker box IF (and this is a real, genuine "if") there is evidence that there is noise or other reasons to doubt the line. If there’s not, I’m happy to let that go.
One, as MillerC. said (at some point, maybe not here), one can learn to listen with more attention and acuity; a better line creates good conditions in which one can hear more. If one doesn’t do that — because they can’t hear a difference *now* -- then one has blocked that path of growth.
Second, I’ve gone to some trouble already to deal with power — a conditioner, good speaker wire, power cables for my gear, etc. I’ve not gone crazy but I’ve not stuck with stock cords. That approach — not to accept any lowest-common-denominator elements in my system — seems logical to extend to the breaker box IF (and this is a real, genuine "if") there is evidence that there is noise or other reasons to doubt the line. If there’s not, I’m happy to let that go.