This is where Facebook's closed-data policy causes trouble. If they allowed backup to other cloud services or to local disk, users could make a habit of this, and tools would be developed.

FB does have a "download your info" service, but they make it difficult, with manual asynchronous confirmation, and they don't give you certain critical parts of the data (like friends' emails).

Any decent backup mechanism must allow for a frequent, automated backup which is complete enough to be fully restorable.