The article doesn't mention what items you might want to exclude from your backups. For me, it's temporary files that don't need to be backed up, files that are in a folder only temporarily (soon to be moved elsewhere), and large files that I know are already stored elsewhere.
I exclude the following from Time Machine backups:
- /.Trashes
- /Library/Caches
- ~/.Trash
- ~/Library/Caches
- ~/Downloads
- ~/Not backed up
The last one is a folder named
Not backed up, under my home folder, that I purposely created to use for large files or folders that don't need to be saved. For example, a friend wanted help with a project and gave me copies of hundreds of megabytes of photos. I put them in the
Not backed up folder for the few days I was helping. There would be no advantage in having Time Machine take the time and disk space to back them all up, since these were only copies of the original files and I would soon erase them.
I'm tidy about my Downloads folder, so I don't let the contents build up over time, but I know people who have hundreds of files, many of them important, living in their Downloads folder because they never "filed them" elsewhere. If you can download them again, they might not need to be backed up, but if you edit files there or can't get them back if needed then you should not include ~/Downloads in your Time Machine exclusion list.