How often a PC attempts to capture the config it backs up. GE-Enforce runs every cycle, so this is what stops a bay collecting several times a day. A capture that finds nothing changed writes no revision - it only records that the check happened.
A backup is judged on when it was last CONFIRMED, not when it last changed. An unchanged config writes no revision, so a machine stable for months is healthy - the one to worry about is the machine whose backup stopped running.
Both off by default, and dedup already keeps growth low - a revision appears only when a config really changed. Retention exists for a value that flaps. The newest and oldest revision of a chain are never pruned.
Note: pruning removes database revisions only. Files written to the share are not deleted, so enabling this on a share-backed kind leaves snapshot directories with no revision pointing at them.