How to compare file dates for backups with automator and applescript

Hello. I have an external hard drive that I keep backups of my music on. I want to simplify copying new music to the HD, but I have the problem of forgetting to do so as soon as I get the music. Is there any way that I can create an automator and/or applescript script that can compare the dates of a folder. Then, if my computer’s date and the External’s date are different, it recursively checks all the folders inside that folder. If a folder has been changed, but contains only files, then the files in that folder are all backed up to the External (or, even better, just the new files), until the script continues on with the rest of the folders.

Sorry if it sounds picky, but that is exactly what I want it to do (unless there is a better way). Thanks a lot!


I recommend to use a tool like SuperDuper oder DejaVu (there are a lot more), which is able to
do differential backups, i. e. only the new or changed files will be copied.