I am trying to figure out how to keep back ups of pics/videos from my MacBook and be able to keep a certain amount of disk space free on my MacBook. As I understand it, Time Machine makes a backup of snapshot of the Mac. If I delete any files from my Mac (to create space) after they have been backed up in a snapshot, those files will not be in the next backup in Time Machine. I want to be able to add files in specific folders to my MacBook, back them up to the external device such that it gets incrementally updated with new files and be able to delete files on MacBook to create space on my HD. Any suggestions on how to do this with fast and reliable backups? Looks like Time Machine does not allow this. Even if a file is one of the older back ups and I want to restore it, there will be no easy way to keeping track of which snapshot has the specific file.