Doing some long avoided housekeeping since we're stuck at home, and I came up with a good self-brain-hack.
For each object, ask: "Pretending I don't already own this thing, would I buy it for 25 cents?" The answer is usually no.
Otherwise the implicit question is "Can i think of ANY conceivable scenario where I need this thing someday?". That answer's always yes. Thus, hoarding.
I think this is what Marie Kondo was getting at, but "would buy for a quarter?" works better for me personally.