Just how many outlets do you need for your stereo?

ONLY ONE.

A 15 amp standard house outlet will supply about 1800 watts. To be conservative, say 1500 watts.

This will EASILY cover most amplifiers of up to about 300 watts rms/channel, as well as ALL the other paraphernalia like tt, preamp, dac, streamer, CD player, etc, etc.

It is actually best practice to connect ALL your equipment to the SAME outlet to avoid ground loops.

If you use more than one outlet and their grounds are not at EXACTLY at the same potential (even a tenth of a volt difference is enough), you will have a ground loop and you may not be able to get rid of the hum & buzz, unless you use a ground lifter, which may be illegal in your locale.

Stick to ONE outlet.

spatialking,

As long as you are on a single outlet, you can have a walwart extender to plug in those wide annoying boxes :-)  Since the plugs are very close to each other in electrical terms, it is unlikely you will have a ground loop problem.

This one has 10 physically widely spaced out ports for almost everything and rated at full 15 amps.  I think you can connect an entire studio to it :-)

https://www.amazon.com/TESSAN-Mountable-Extension-Security-Safeguard/dp/B07VVKSYCZ/ref=sr_1_8?dchild...