What made you put together your first 2nd system?

Clear from the OP that second systems are not done out of dissatisfaction for the first, pace ebm. 

If I start a second system, it would likely get its fuel from two different motives; first, I have extra gear that is not worth selling nor worth giving away. Example, I have some Adcom gear that sounds quite decent but is not worth much. It could form a nice second system.

Another motive might be to have a solid state system with different power and speakers which crave it OR a low power system with high efficiency speakers and a sweet low-watt tube amp.

sensibility

First 2nd system came about when we bought a log home in the mountains.  Wanted some music so had an extra CDP and tuner. Bought a new Grommes PHI-26 and used Klipsch Quartets.  No Phone or internet.

Three systems, one in each of the places in my house where I spend a good deal of time, living room, office and garage workshop. All of them are tied together by WiFi so that I can move from place to place without any interruption in what's playing.

I spent a lot of time at a friend’s house and the only music available was from their flat screen’s speaker via cable box.   They thought it was fine. Drove me crazy.  I brought over an extra Cary amp, Marantz DAC, N802s and Cardas cables. Loaded Roon and Tidal on their PC and I could not be happier.

Recently in another thread, oldhvymec gave me the idea to keep my extra cables broken-in on a second system. Well I have one, it is just at a friend’s house.