iCloud for off-site copies
Every month I copy my important Q folders to an external drive. If I were to do this using iCloud, would I also need to keep local copies?
Currently, iCloud isn’t suitable for A making proper backups of your Mac, but is valuable for keeping off-site copies of important files provided you don’t rely on always having instant access. Like all cloud services, it isn’t guaranteed to be available at all times.
When you put files in iCloud Drive, they’re copied up to the iCloud servers, but the original also remains on your Mac. If the copy in iCloud changes, by editing it using a different Mac or device, that’s synced back to your Mac, keeping it up to date.
Behaviour changes if you enable Optimise Mac Storage in System Preferences > Apple ID. That lets macOS decide when to ‘evict’ files from local storage, leaving only a stub on your Mac. The Finder then marks those with a cloud and downward arrow icon. So long as there’s ample free space on your Mac’s storage, that process normally only happens with files you haven’t accessed recently, but if local storage gets tight, macOS can evict more. Once evicted, you can still use the file, but it has to be downloaded from iCloud first.
If that method doesn’t meet your requirements, you can keep additional local copies, but you’ll then have to work out how to keep them in sync with those in iCloud Drive. Obviously, you don’t have to enable optimisation, but macOS seems only too keen that you do.