Dave uses iDrive as his main backup option, but he wants to be sure he has a good backup to his backup. This is mostly for his media collection, which amounts to 1000s of songs and DVDs. He has an 8TB hard drive. Leo says there are three kinds of backup ... image backup for quick restore, a standard data backup, and then an incremental backup, which is used for when people update a file and the backup only archives those changes. This could also include versioning. Then once people restore from the full backup, they can then restore the incremental changes as needed. Leo recommends image backups for when he has the computer in a perfect and stabile condition, a standard data backup on a weekly or monthly basis, and then the incremental backup every night, or as a file gets changed.
What program should Dave use? Leo suggests a synchronization program like SyncThing for the mac. It takes attention to set up, but once he does, it's very reliable for incremental backup and sync. Another option is SuperDuper. He can set it up to schedule either or both incremental and full backups. On Windows, Leo likes Second Copy.