Quick System Building Pop Quiz:

For me it's 1 simply because I only have the space for 1 system. I'd love to have a 2nd system to tinker with. I own two streamers, two Dacs and two amps at the moment so I am most of the way there but no place to put it!

@jond the good news is in cases like yours there are lots of very fine and affordable options out there to explore with headphones, earbuds, portable DACs and amps, etc. 

@mapman 

You are correct… I seemed to have a couple other systems. They have never been extra systems, but for a special location.
 

I have a system in my office. It started with cheap PC speakers twenty years ago. I used to work a lot. Typically a couple hours or more a night. So, I upgraded one piece every once in a while… until it was pretty good.

I started a headphone system at work twenty years ago. Same kind of thing. It was in between upgrades of my main system. Well, I am an audiophile… so, slowly over the years I upgraded it. 
 

For most of my five decades I never had a second system of any kind. But I would not create another sit down system for the purpose of normal dedicated listening.

Number 2 since I'm still trying to decide what "good sound" is.

The first 80% is a lot cheaper than when going for the last 20%. Meaning before I go for the last 20%, I better have the basics right.

It depends. If the system is very good, I’d definitely pursue optimizing it. It’s a great way to make subtle personalized changes to suit your tastes and room. I chose that path 30 years ago with what I thought was a really nice sounding system, and have refined it since....isolation, wires, bi-amping, power supply upgrades, mods, tube rolling, etc. Nirvana on a budget!

Starting from scratch can cost a lot of money, and is a shot in the dark whether or not it’ll get you any closer to where you want to go.....it’s so subjective and room dependent.