Is it necessary to backup S3?
dagw: At the end of the day it's an economics question.  How much might you lose in a worst case scenario if you failed to recover some vital data?  How much extra will it cost to back up your data to a second place?  If the answers to those questions are "everything" and "not a lot" then there is no reason not to backup your backups.As a general rule important data should be backed up to (at least) two separate places, and in this scenario I'd consider S3 to be one place.