If you want a refreshing sleep night after night, it’s important to know how often to wash your bedding. Depending on the type of bedding you have, how often you wash can fluctuate. Below are some common rules of thumb for how often to washing bedding: Sheets: Once a week Pillowcases: Once a week Duvet cover: Once every two weeks Comforter: Once every few months These recommendations also vary depending on certain factors, such as whether you sleep with a pet or spill something on your bedding.