I only own a single duvet, it's quite lightweight, I have a bunch of blankets to put on top if it gets cold (and a weighted one if I want to feel extra cozy).
"What is your duvet is it down or manmade and have you changed to your winter duvet yet, me im on down tog 4 lol"
We're still on our 1;tog 4 tog is our winter duvet lol