If I'm subscribing to a collection that has 1000 docs, will I bee charged for 1000 reads as soon as the subscription is initiated? Per https://firebase.google.com/docs/firestore/pricing#listens I'd say no, but per https://stackoverflow.com/a/60356400/9118098 I'd say yes.
I'm asking as I have an "ever-growing" calendarEvents collections, and am trying do decide whether it'd be better to structure data as
calendarEvents/{calendarEventId}
or
calendarEvents/{2022}/March/{calendarEventId}
to keep the cost down, as the latter allows me to subscribe to the current month only.