Don’t replace it – swap it for a brush. That’s one interpretation of a 2022 study, which found more bacteria on the average washing-up sponge than there are people on the planet. The authors claim it’s impossible to stop bugs growing on a wet kitchen sponge unless you change it daily, whereas a brush harbours fewer germs because it dries out faster between uses. If you do prefer a sponge – and you’re not alone, as people in eight out of ten European countries do – then you might be relieved to know that neither tends to collect the kinds of germs that cause diseases. (Which is enough to convince me that I never need to replace it. But that’s our dirty little secret, right?)