According to Barret, you should be washing your actual pillow at least every three to six months. For most people, twice a year will suffice. But in certain circumstances, you may want to clean it more often. “If you sweat more during the night, have more sensitive skin, or have allergies, you should wash your pillows more often—about every three months or more, if you feel the need,” Barret says. Why does your pillow need a wash if it’s covered in a case? “Pillows are perfect hosts for debris, dead skin cells, sweat, moisture, skin oils, and so on,” explains Alex Savy, a certified sleep science coach and founder of SleepingOcean. “If you leave all of that stuff be, it may attract dust mites. And sharing your sleeping space with those guys can cause allergies, itchy or watery eyes, skin rashes, and even increased risk of asthma.” As for the best way to wash your pillow, Barret says it depends on what type you have. Down and synthetic down pillows typically can be washed in your laundry machine, while foam pillows should only be spot cleaned. And putting a memory foam pillow into the washing machine is going to mess it up because it can absorb all the water from the cycle. “Read the tag first, as most manufacturers offer suggestions of the appropriate water temperature and washing cycle for each specific pillow type,” Savy suggests. Even if you’re washing your pillow regularly, you still need to change it out often. Barret and Savy note that you should replace your pillow entirely every one to two years. Read on for signs you need to replace your pillow, and for more items you should be changing on the regular, check out This Is How Often You Should Really Be Changing Your Underwear. Savy says noticeable lumps in your pillows are a good sign they need to be replaced; and according to Barret, the same goes if your pillow feels too flat. And for more things to swap in your bedroom, find out if you have The Bedroom Wall Color That Is Ruining Your Sleep.ae0fcc31ae342fd3a1346ebb1f342fcb If your pillow is permanently stained, it may be time for a new one. Barret says any pillows that have formed a yellowish color that isn’t gone after washing should be replaced. And if you’re already doing some scrubbing, make sure you tackle The One Thing in Your Home You’re Not Cleaning That’s Making You Sick. While some odors disappear when you wash your pillow, others may stick around. Savy says that lingering, stubborn odors are a “good sign that your pillow is probably way too old for you.” And for more helpful tips and tricks for your everyday life, sign up for our daily newsletter. The National Sleep Foundation has an easy test for seeing if you need a new pillow. According to the organization, you should fold your pillow in half and see if it stays folded while you’re not holding it. If it does, you need to replace it. And for another object that needs more cleaning attention, check out The Filthiest Spot in Your Home Is 12 Times Dirtier Than a Toilet Seat.