The CrossFit Gym where I work out is a LARGE wide open space, but the only WiFi in the place was from the Zyxel DSL router provided by the ISP (CenturyLink in Seattle). It's only a 5 Mbps DSL pipe, but the main problem was the very weak WiFi located in the office near the front of the building trying to maintain a connection to devices at the back of the gym... as well as a lot of WiFi interference from neighboring offices.
The gym owner has an HP printer, two Nest cams, two Intel mini-PCs, and a Samsung tablet attached to her WiFi network. But the big problem was that Pandora music streaming from the tablet (and connected to the stereo system in the gym) would ALWAYS lag and cut out. It was a constant source of complaint among gym members. Music cutting in and out during workouts is distracting.
I took an old UAP-Pro that was no longer in use at any of our three sites (I'm running all "AC" units now), created a new site for the gym in my controller, connected the UAP-Pro to her DSL router, shut off the WiFi on the DSL router, and created a private SSID only for her "internal" devices.
Then I borrowed some graphics from the gym's website to create a guest password WiFi login screen on the controller (that AngularJS setup is a breeze). She thought I was a magician. The music now streams with zero issues, and gym members love guest WiFi access (since it's primarily the same "guests" using it, I set the guest expiration to 30 days so members only have to re-authenticate once a month).
So if you've got old network equipment sitting in a corner of your office, don't forget there are plenty of non-geeks out there who will think you're magic if you use it to upgrade their network. So maybe donate that gear (and a touch of your expertise) to a small local gym, dojo, church, or anywhere else where you're a "tribe" member. And if you're a networking professional, that might be a good marketing tool if they ever want to get REALLY serious about their network.
I'll probably get her set up with a CloudKey eventually, so I don't have to keep their site on my personal controller. But for now, it's zero maintenance, so I'm in no rush.