I used to be able to hear feedback in my stereo when I turned on lights in the dining room. An independent line ended that. They do matter, and not just for peace of mind. I actually ran two to my system which lets me keep my amps plugged directly into the wall while isolating the front end on a different line. If you can afford the wire cost, I'd recommend having the electrical pull the second line too. The added work is minimal and you might find that you want it later down the line.
Honestly I wish I had three, one for the amps, one for the front end, and a third for anything with switching supplies. The further down the road you go, the more all of these power supply issues matter. In my system it's usually manifested as a greater ability to relax into the music. I clench my jaw when exposed to high frequency distortion and have ceramic tweeters that are more than happy to pass that information along.
Honestly I wish I had three, one for the amps, one for the front end, and a third for anything with switching supplies. The further down the road you go, the more all of these power supply issues matter. In my system it's usually manifested as a greater ability to relax into the music. I clench my jaw when exposed to high frequency distortion and have ceramic tweeters that are more than happy to pass that information along.