I’ve always used dd (if=/dev/mmcblk0) + sshfs to backup the entire sd card daily at midnight to an ssh server; retaining 2 weeks of backups.

Should the card die, I’ve just gotta write the last backup to a new card and pop it in. If that one’s not good, I’ve got 13 others I can try.

I’ve only had to use it once and that went smoothly. I’ve tested half a dozen backups though and no issues there either.