Backup of Cradle databases is an important topic. We believe that there are two types of backup to consider:
Image backups have the advantage of being quick to take and to restore. However, it is not possible to recover individual items from such backups - well, without reloading the entire database and exporting from within in.
Export backups have the disadvantage that they are comparatively slow to create and slow to restore, but they have the dual advantages that they are guaranteed to be forward-compatible with future versions of Cradle, and it is possible to restore individual items and cross references from within them.
If possible, we recommend that you do both!