Currently in use on one of my test servers. But have also a modified version running on my MacBook, if things go terribly wrong. So instead -mtime +30 I use -mmin +4320 (3 days) and extented the DATE_TODAY variable. So I have now always a backup of at least 3 days (every 15 minutes) of my MacBook saved on my NAS. (Of cause only if my MacBook is connected to my home network).
Demo: https://codebrauer.github.io/27daysofcode/016_2017-01-16_Shell_Simple-DB-Backup/