Should I remove after using "addListenerForSingleValueEvent"

Question

As the document says, listener for SingleValueEvent only run one time.
Then is it unnecessary to remove listener after using it like this?

final Query query = getChatsRef().limitToLast(20);
query.addListenerForSingleValueEvent(new ValueEventListener() {

    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
        query.removeEventListener(this);         
    }

    @Override
    public void onCancelled(DatabaseError databaseError) {
        query.removeEventListener(this); 
    }
});

Answer 1

No. Removing the listener as you do in your snippet of code is not needed.

The only reason you might want to remove a once listener, is when the listener hasn't fired yet. The only time I can see that happening is when you're not connected to the Firebase servers and the location you're inspecting is not cached. That should be a fairly small number of cases.