Retention answers a recovery question
Decide how far back you may need to recover before choosing daily, weekly, monthly, and long-term versions. Synchronization alone is not retention.
Practical pattern
Keep frequent recent versions, reduce frequency as versions age, and review capacity as change rate shifts. Set exceptions for irreplaceable work.
Use the calculator
Use Backup Retention Calculator to estimate capacity, then test restores from the retained versions.
Limit
Compression and deduplication vary with data and implementation; do not treat an estimated saving as guaranteed capacity.