We recommend you do a long term backup (to glacier archive) and a short term backup.
You can run your long term (eg. 180 days retention) backup weekly. Your short term (eg. 7 days retention) could be ran every 24 hours.
Because AWS glacier archive is so significantly cheaper. Within TCorp we backup our databases daily to weekly to it depending on the criticallity of the data. Note that data retrieval is véry slow so we should still use short term storage on external services.