I would like to add a functionality to this fantastic script. We've noticed that old databases from customer that went away long ago sta in the 'weekly' and 'daily' directories indefinitely.

Can we sugest to improve the script?

Delete backups older than retention period

find "$BACKUPDIR/daily" -type f -mtime +7 -delete
find "$BACKUPDIR/weekly" -type f -mtime +30 -delete
find "$BACKUPDIR/monthly" -type f -mtime +90 -delete