I am about to pick up a new MBP to replace a 2010 model. I currently have TM backing up everything less a couple of folders from Dropbox to an external drive. When I go to my external drive, I see folders from each day of a backup with all of the information in each folder (replicated each day). Shouldnt it just be one backup with all changes in it? Seems like it's taking up tons of unnecessary space. Thanks.