How many systems do you have?

Four.

Main one in the living room, smaller one in the dining room, former main components in the bedroom and one in my office. All that in a townhouse of less than 1,000 sq ft :-)

Two is a bare minimum.  One is the main system, the other is made up of hand-me-downs from the main system, so you get more mileage out of replaced components before they leave the premises.

In short time, when I take delivery of my new amp I will almost have two systems.....   I have doubles (or more) of everything to build a second system,  except speakers.     So basically I'm now on the lookout for speakers 

I have enough audio equipment to have 7 complete systems....that's speakers, receiver or integrated amp,pre amps,Solid State or Tube (pre amps, receiver ,amps or integrated amp) cassette decks,and or cd players ,plus Speakers ,with rear speakers also....I'm like Crazy Eddie's, I'm Insane....

Three separate systems:

1 - Living Room: 2-channel, old but tasteful SS gear from the late ’80s, Boston Acoustic A40 speakers (wonderful little 2-ways) + cheap subs. This is strictly for casual music during dinner parties & social gatherings

2 - Main Home Office System: Very complicated because the DAC has dual RCA outputs. One pair goes to an excellent preamp/headphone amp (Violectric V281) used as main system preamp + headphone amp. This path goes to an electronic crossover that feeds a big class D amp (for vintage KEF 103.2 speakers) + JL Audio 10" sub. 2nd path is a 2nd headphone amp. 2 people can listen to headphones at the same time on different paths.

3 - Side-System/Home Office: Another DAC with dual RCA outs feeding 2 headphone amplifiers (Headphone listening only).

Years ago I had a much bigger 2-channel system that engulfed the LR of our 1st house. Those were the days...