This works fine and zips up all the files into Drive1.zip.
However, when I run this next time, I would like it to not have to re-compress all the files, but rather just add new files, update any files that have changed, and delete files that no longer exist.
So I tried this:
zip -f -u -r9 /mnt/Backups/Drive1.zip /media/Drive1/Files/