I just have “users:all” and a “users:#{user_id}” - then the “public” stuff goes over the :all chan and the “private” stuff over the :user_id chan..
but all depends of course.. if you have 10k different chat rooms you definitely want a chan for each and dynamic join/leave on the client..
since I load all state from the get go in an “after_join” I maintain all state updated through chans no matter where the user navigates around (ie. no spinning loader etc.) - but a larger app with loads of data could be different..
eg. in the admin app (which is react js - but still redux-observables) I load data dynamically as you navigate around (since “data” is big)
so +1 on a generic chan - and then I assume requirements sooner or later will need a user_id chan… ymmv but KISS always win 
