I use the built-in (windows) robocopy.exe to backup my music files.
Thanks to the "last modified" date for every metadata change (Mp3tag -> File -> Options -> Tags -> "Preserve file modification time when saving tags" UNCHECKED) robocopy.exe detects every change I have made and copy such files to my external hard drives and NAS.
Every unchanged file will not be transferred.
With this basic form of "incremental backup", you are sure that you have a 1:1 master copy without the need to restore several different smaller incremental backup parts.