Other than with the messaging application, you don't want the feed with posts to reload every time a new post has been posted by any of the people in your network. Besides subscriptions, there are other ways to have (near) real-time data flows with GraphQL and Apollo, namely, polling. With polling, you can retrieve a query from a useQuery Hook once every n milliseconds, saving you the complexity of setting up subscriptions.
Polling can be added to the useQuery Hook, like this one in client/Screens/Posts.js. By setting a pollInterval value on the object parameter from the useQuery Hook, you can specify how often the document with the GET_POSTS query should be resent by the Hook:
...const Posts ...
