How long does Home Assistant Keep sensor data?

10 days Long-term statistics are different than the other objects in the database, which are stored exactly as they happened and are automatically purged after a period (default is 10 days). Statistics are never purged. Because they are summarized every hour, they only create 24 entries per day.

How long does Home Assistant retain data?

10 days It is this setting in the recorder integration: https://www.home-assistant.io/integrations/recorder/#purge_keep_days it lists the default as 10 days. You can also limit the amount of data stored by excluding entities you are not interested in the history of. Nov 26, 2021