No. You can use one Sonos account on as many households (bound collection of Sonos devices) or networks (separate subnets) or SSIDs (same subnet).

To answer “how” you need to be more explicit about “multiple networks”. Do you mean two houses? Or two subnets/VLANs on the same physical network? Or two SSIDs on the same subnet? Or something else??

Two houses. Also need to change internet connection in one of the houses … new router

Two houses is the easy case. When you go to the second house you might have to “forget this system” (to forget the old system), or you might have to “connect to existing system”. Much easier than the other possibilities.

It does vary. I have systems in three houses. I don’t have to do a damn thing any more to switch between them, just run a fresh instance of the Sonos app (ie force kill a version that may have connected to the prior version). Or I can use my own app, which doesn’t care about such things at all, it just connects, and prompts if it finds more than one on the same network.

Some music services will not simultaneously play in two houses.

That’s not a problem for us. I talked to Sonos and they walked me through a connection. Now good at vacation house. Won’t know for a while how it’s working at home. Thanks for all the help and suggestions.