Link: Create a “Do not backup” folder
This is just a brilliantly simple idea: create a folder on your computer that’s excluded from Time Machine/Backblaze/Dropbox/Sync/whatever and use that whenever you need to temporarily store something you would never want to be backed up.
The example in the podcast is plain-text files of all your passwords. It might not seem like this sort of thing would crop up often, but it also seems like exactly the sort of thing that’s worth spending five minutes on now to save yourself a bunch of time, faff and potential unbacking-up later.