We started using Spanning Backup this school year, it backs up the emails every morning but does not keep a daily backup for those, just keeps that days backups. However, for Google Docs, Sites, and contacts it keeps a running daily backup so you can go in at anytime and for any day and restore anything you need. We have not needed it much yet, thankfully but I did have to restore the contacts for our Superintendent which worked perfectly. It is a paid solution but it really does give piece of mind and for only around $3,000, though we are a smaller school.