How does firestore realtime listener billing work

[jtdLab]

Given an app which watches a collection with 10 elements like this:

final messagesSubscription = firestore.collection('messages').snapshots().listen((e){
// Use the update in the app
});

// After some time
messagesSubscription.cancel();

Some time later the app again calls:

final messagesSubscription = firestore.collection('messages').snapshots().listen((e){
// Use the update in the app
});

Does the 2nd call cost the 10 initial reads again? Or is the listener reusable in a certain time frame?