Backup Your iCal Data

The setting above keeps iCal from becoming cluttered with old events. However, if you want to keep a record of schedules, appointments, and events, you can uncheck the “Delete events” checkbox and let iCal permanently store your information.

When you choose “Back up Database” from the File menu, you can save dated backups to a backup folder. Later you can revert to any previous version of the database.