I agree cloud based backups like Dropbox just sync in the background. Got any souce code store it in Github or Bitbucket.
Documents and source code doesn't take up much space. Unless you want music and video files which iTunes can always sync for you to your Apple mobile device.
I use a USB hard drive to back up my Thunderbird and Firefox profiles. Also my downloads and other stuff too big for Dropbox. $100 for a 4T USB 3.0 hard drive is cheap.
Sync is not backup. If you corrupt or delete a file, the destructive action will get propagated as well. Time machine and many other backup systems gives you access to previous versions of files and folders.
Documents and source code doesn't take up much space. Unless you want music and video files which iTunes can always sync for you to your Apple mobile device.
I use a USB hard drive to back up my Thunderbird and Firefox profiles. Also my downloads and other stuff too big for Dropbox. $100 for a 4T USB 3.0 hard drive is cheap.