How Often Do You Really Need to Wash Your Sheets?

Probably more than you think.

Every morning when Libbey Castle wakes up, she strips her bed and chucks her sheets into the washing machine. It doesn’t matter if it’s a weekday or the weekend, if she has a light or a busy day ahead, if she slept well or tossed and turned all night. The sheets will be washed. 

“I let them do their thing, and I go make coffee feeling happy,” says Castle, 30, who lives in Washington, D.C. “Then I throw them into the dryer before I go work out. I come back, I grab a shower, and the sheets are done. I throw them on the bed, and then I start my day.”

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Castle finds the reactions to her daily washing routine to be amusing. When she hosts a book club event or dinner, the group always asks the newest attendee if they’re aware that she washes her sheets every day, and during Zoom meetings, her colleagues are excited to catch a glimpse of her famously clean bed. Castle tells them that knowing fresh sheets await her boosts her spirits throughout the day.

Health experts agree that Castle is onto something: Most of us could benefit from washing our bedding more often. Sheets, pillowcases, and comforters can harbor dirt, germs, and allergens that affect our skin and overall health, says Dr. Hannah Kopelman, a dermatologist in New York. “It’s a build-up of all these contaminants, and eventually that could lead to skin irritation and acne breakouts,” she says. “You might notice your skin feels like it has clogged pores or folliculitis,” which happens when hair follicles become inflamed. Or maybe your allergies, asthma, or eczema are flaring up because the dead skin cells we shed while asleep are attracting legions of dust mites. All are good reasons to make a trip to the laundry machine.

But what’s the sweet spot for washing frequency? We asked experts to share their preferred intervals—plus tips on how to do it well.

Sheets

At a minimum, you should wash your sheets once a week. But a variety of factors call for more frequent washing. One is the summer heat. “We obviously sweat more in the summer, and that can lead to bacteria and odor on our sheets,” says Tonya Harris, an environmental toxics expert who wrote The Slightly Greener Method, which dispenses tips on living a more sustainable, eco-friendly life. Plus, allergens like pollen can travel inside with you, so washing more frequently can help reduce symptoms you might be experiencing. It’s also a good idea to wash your sheets more often when you’re sick or if you sleep with pets, Harris says. In those cases, every three to four days should suffice.

Check the label on your sheets for care instructions before washing. While cotton can (and should) be washed in hot water, some materials, like silk and satin, can only handle lower temps. Use a gentle detergent, and then tumble dry on low. Keeping an extra set of sheets on hand can help cut back on wear and tear from extra washes in the summer, Harris points out, and showering before bed is another good idea. Doing so helps reduce body oils, bacteria, odors, and allergens, potentially extending the amount of time you need between washes.

Read More: Why You Sweat So Much at Night—And What to Do About It

Comforters and other blankets

If you use a blanket as your top sheet, it needs to be washed at least once a week. But otherwise, if they’re not directly touching your skin, plan on washing blankets and your comforter every two to three months, says Kathleen Razmus, director of operations, training, and development with ZIPS Cleaners, a dry-cleaning franchise. “Dust and dirt will accumulate, so it’s good to freshen it up,” she says. “If the comforter is touching your skin, that’s different, and you might want to make it more frequent.”

As with all bedding, make sure to check care labels closely. Wool blankets often can’t be laundered, which means you need to spot-clean them. And sometimes comforters are simply too big to fit in at-home washing machines. If you suspect yours is over the size limit, Razmus advises taking it to a cleaner or laundromat where you can access large-capacity washers. Or, invest in a duvet cover that protects the comforter—it should be much easier to regularly toss in your washing machine.

Pillows and pillowcases

When the bedding company Amerisleep collected samples from volunteers’ sheets and pillowcases, they found that pillowcases had the most bacteria: up to 5 million colony-forming units per square inch after just one week of use. It makes sense. “Pillowcases are the landing pad for your skin, hair, and all the oils and dirt carried with them,” says Jason James, who runs Dustpan & Brush, an organic home cleaning service in Melbourne, Australia. He recommends washing them at least once a week. People who have sensitive skin or allergies often benefit from a more frequent routine, like every three to four days.

If that sounds like a lot, there are a few things you can do to reduce potential grime, James says: Shower before bed, and practice good hair hygiene, especially if you use lots of products or have long locks. “Wrap your hair in a scarf, or use a hair towel to prevent transferring oils and products to your pillowcase,” he suggests.

People often forget about their pillows, but they need to be washed, too. In general, once per season is the sweet spot, though you can do it monthly if you prefer, James says. Most can be popped into the washing machine, but it depends on the exact material and fill. Soaking buckwheat hulls, for example, will ruin them. Check the label to figure out what’s best; if the pillow can be washed, use the gentlest washer and dryer settings possible. Otherwise, you’ll need to do it by hand. James likes this method: Mix 1 teaspoon each of vinegar and a non-oil-based soap (like organic castile) in a basin of water. If you like essential oils, you could add a tiny drop to elevate the aroma. Then, put the pillow in the water and gently squeeze it; when you’re done, refill the basin with clean water, and rinse the pillow out until there’s not a trace of soap. Then place it on top of a clean towel, and give it a few hours to air dry.

Mattress pads

People tend to overlook their mattress pad, but it’s a good idea to wash it every two to three months, Razmus says. Given that it helps protect your mattress from sweat, spills, bladder leaks, dust mites, and dead skin, it can get pretty dirty. Check the care label closely; different materials call for different washing techniques. Cotton mattress pads, for example, can typically be machine washed on a gentle cycle, while wool requires dry cleaning or hand washing. Memory foam mattress pads typically aren’t designed for machine washing, but you can spot clean stains with a damp cloth and soap.

Read More: What’s the Least Amount of Sleep You Need to Get?

Your mattress

You read that right: Your mattress requires regular maintenance. For starters, every time you strip the bed, let the mattress breathe for a bit, rather than immediately putting on a new set of sheets. “Leave it for a few hours with some windows open,” James advises. Stagnant air and covered mattresses encourage dust mites, allergens, and mold spores to thrive, so this small step can go a long way.

As for actually cleaning that big, clunky thing? If you want to tackle the job yourself, Harris advises vacuuming it two to three times a year. If you discover it smells, sprinkle a thin layer of baking soda over it, let it sit for a few hours, and then vacuum it up. Ideally, you’ll then flip the mattress, and vacuum the other side, too. (She’s not great at that part, she acknowledges—flipping a king-size mattress isn’t exactly fun.)

If you’d rather outsource mattress cleaning, most cleaners will bring a high-grade steam sanitizer into your home, James says. The process “kills all the nasties in their tracks, and has your bed ready for use in less than an hour or two.” He suggests sanitizing every two years. That way, you can sleep peacefully at night knowing there’s nothing but sweet dreams lurking in your bed.