A plain sofa is one of those things that looks fine until you see one that looks great, and then you cannot unsee the difference. White duvet sets are doing serious work in living rooms right now, thrown over sofas that need some help without needing a whole new piece of furniture. It is a trick that sounds too simple and works better than it has any right to. The key is the quality of the fabric. A thin duvet cover draped over a sofa just looks like a thin duvet cover draped over a sofa. What you want is something with enough weight and texture to look intentional, to read as a considered choice rather than a cover up. We have been looking at sets that bring that quality, the kind where the cotton is substantial, the stitching is clean, and the white is a proper white rather than something yellowing after two washes. These are the ones that actually change the room.