We spend 1/3 of our lives in bed, but very few of us give much thought to the maintenance of our duvets and pillows. Every night, you emit more than ½ litre of fluids, some of this in your breath but most of it in the form of sweat.
A portion of this sweat is absorbed by your duvet and pillow, which gradually causes their down and feathers to clump together. The duvet will feel heavier, and the clumping results in a decrease in insulation value

It is important take your personal needs into account when choosing a duvet. Will you be using the duvet during the summer or the winter? Do you like to sleep with the window open? Is your mattress well insulated, or does it allow for air circulation from below? All too frequently, people buy quilts that are too warm. It is certainly possible to have too much of a good thing: When your bed is too hot, you risk disturbing your sleep cycle and may miss out on the deep sleep that lets you wake rested and refreshed.
It is also important that your duvet is at least 30 cm longer than you are and at least 30 cm wider than your chest size. American-style double duvets have also grown in popularity, and in this case, you should ensure that the duvet is at least as wide as the bed itself. Remember though, a double duvet is only a good idea if both you and your partner have the same needs. There is no point in you freezing while your partner sweats!