My system: play 5 (1st gen), play 5 (2nd gen), play 3, play 1 and a boost.
For a couple of years I had been struggling with this setup. The play 5 (1st gen) was constantly dropping out sometimes bringing other speakers offline at the same time. The thing that was confusing me was that using Wi-Fi (not boost) the system was stable. I occasionally lost signal in the far reaches of the house so I bought a boost. That’s when the problems started. The play 5 would play for about 30 seconds then freeze, drop off the system to reappear a couple of minutes later. To be fair the router had its problems with dropouts on other devices but sometimes Netflix (for example) would be fine and the sonos would drop out. Only after a lot of searching on forums and by switching ISP (who provided a new modem/router) is my sonos boost setup now as stable as a rock – no issues at all. The problem lies with the Asus DSL-AC68U. The router itself is fine – however the built in modem is not stable and drops the connection on a regular basis. I hope that this helps others who might be suffering from similar problems.