Although S3 is durable against data loss, there's a risk that programmatic errors can result in data loss. A prudent solution is to periodically replicate the lsst-the-docs S3 bucket to make it possible to recover data. This isn't a complete backup (solution; it'd be good to have cold storage like AWS Glacier, but it's a start.

Possible solution: https://eladnava.com/backing-up-your-amazon-s3-buckets-to-ec2/ (discusses using the AWS CLI to trigger S3 bucket replication).