On canned (water bath an pressure) I take the rings off. If a lid pops (looses a seal) er really lets go, I'd rather know bout it an a ring can sometimes keep a lid from poppin off. On my vacuum sealed jars, I leave a ring on em. Don't know if be needed er not, just a strange old hillbilly way.
Like Old Coot, I take mine off except for the vacuum sealed jars. If anyone has the misfortune to be in the vicinity of a tornado, be sure to check your lids, the pressure can unseal them.