iNotePad can automatically backup your databases when you quit iNotePad.
Backups are saved in the folder Backup inside iNotePad folder (default location is ~/Documents/iNotePad/). You can move this folder wherever you want and leave an alias of this folder inside iNotePad folder. This alias must be named Backup.
You can setup in iNotePad preferences when you want to backup your database (once a day, a week or a month) and how many backup copies you want to keep.
All the backup copies of a database are gathered in a folder "<database name>" inside the Backup folder. Each backup file is named "<curent date> - <database name>.iNotePad".
You cannot open a backup copy directly in the Finder. You have to move it to the main folder iNotePad then relaunch iNotePad.
Note that iNotePad backups each database only when you've used it then closed it (quit iNotePad or switch to a different database).
Encrypted databases will be backed up... encrypted.