How often you should wash your sheets (and how to leave them really clean) Experts recommend washing or changing them once a week. Pillows should be changed every one to two years. Using a pillow protector can help minimize dust and bacteria. We have established how often sheets should be washed once a week, ideally.
The bottom line is that you should change the pillowcase at least once a week. That's even if you don't sleep with a pillow under your neck or face. Of course, if you want to do it every few days, that's even better. However, in a realistic world, once a week is enough for most and helps prevent the disgusting buildup of skin, dirt, and oils.
To avoid this build-up, it's important to wash all bedding regularly. Tierno recommends washing sheets and pillowcases every two weeks and duvets every three months or so.