If you own a desktop Mac, you probably use an external drive for Time Machine. If you use a portable Mac, most likely not, and according to the Tidbits article, you’re not alone. The portability of the Mac is hindered by having an external drive hooked permanently. I, personally, have a different strategy: I use a Synology NAS DS720+ with Time Machine enabled to do my backups over the wireless network. It works perfectly, but I don’t do a full backup of my MacBook Air. Files that are part of iCloud Drive are excluded (read more here, you’ll find out why it’s a good idea). In fact, most of the files are excluded, except a few critical folders, outside the scope of any cloud syncing services. Applications aren’t backed up either (easy to recover in case of lost). Backups are small but are just what I need to protect my work.