I have 4 systems--main, bedroom, office, kitchen. The main system (in my Virtual System) is far superior to the others, which I use for background listening rather than more serious listening. I also use wireless earbuds for listening on the go, and they are actually better than the speakers in my three lesser systems, so maybe I have 5 systems.
Aside from having the music in various rooms, the office system was a place for me to put components that I had upgraded in the main system, and they could serve as spares if something in the main system went down, which has never really happened.

