So what does backing up a catalogue give you that backing up Raw+XMP/DNGs doesn't? I've ignored existing catalogues or deleted them with total disregard. When I've wanted to revisit a particular collection, I just import the folder, or sometimes individual photos, and I'm back where I was with the original catalogue. I might create a catalogue with a specific photo folder and use that one now and again, but I would never bother to back it up and I don't care if I delete it. None of my work is lost. Am I missing something?