It’s all a matter of degree

I read all the magazines, scour every post on this blamed website, and contemplate what I might do next to improve my system. Then I turn on my stereo and just enjoy the damned thing.

I like simple systems so just quality basics for me but I'll work hard at getting everything right. 

"tweaks" are secondary addition to a system which is supposed to give to the naive consumers his optimal working without ever being optimally embedded...

"tweaks" are most of the times costly ready made products sold to passive consumers as partal solutions at best...

We need a basic method to embed any system mechanically, electrically and especially acoustically...

Knowing that the question of the OP become now meaningless because between those who plug their system in the wall and dont ask for anything more, and those who use some "tweaks" only , and those who go for more "tweaks" chasing their tails, the same ignorance is partaked by them ...

We need a basic method not the buying of upgrades or of costly "tweaks"...

A method is not a sum of "tweaks"....

Acoustic especially is the audio sleeping princess...

I don't really go in for tweaks.  I do use 2 Magic Bricks, one on each Shunyata Hydra 4, but it is just to keep them on the shelf as the power cables tend to pull it back.  As for cables, I bought mostly used and my rule is no more than $400-$500 for a cable.   I spent a lot of time in 2018 dialing in my system and I am a "set and forget" kind of guy, just like the late Ron Popeil.

I can long periods with no changes in my system.  Sometimes a component fails and I need an alternative for a period of time. Then the merry-go-round starts and I read everything that I can to make a considered choice. I typically buy quality used gear to stretch my $.

sometimes a "wishlist" component shows up and I buy it to try it out. Over time, I end up changing just about everything but my speakers (too large and heavy to bother with changing out.)