Quick System Building Pop Quiz:

For a few decades focus was on improving main system, though did play with  fun vintage systems (when vintage gear was quite reasonably priced). A surgery made clear I needed a better bedroom system and remote operation.  Since then, I have had a great time mixing up secondary system combinations and new types of gear.

I’d go for option 2.  I’m happy with my main system right now and I’d love to try some different gear.  I’d really like to try tubes and some horn loaded speakers or some other high efficiency speaker.

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.