Change your sheets once a week, or every seven to ten days if you shower before bed
The standard recommendation from sleep hygiene experts and mattress manufacturers is once a week. That means taking off all sheets — fitted sheet, flat sheet, pillowcases — and washing them. If you shower before bed, sweat less at night, or live in a cool climate, you can extend to ten days. If you sweat heavily, sleep naked, have pets in bed, or live in a warm or humid place, wash them twice a week or every five days.
The reason is straightforward: sheets collect dead skin cells, sweat, dust mites, and their droppings. Over time this buildup creates an environment where bacteria and fungi grow faster, which can trigger acne, eczema flare-ups, or respiratory irritation — especially if you have allergies or asthma. Weekly washing breaks that cycle before it becomes a problem.
Key Takeaways
- Once a week is the baseline for most people; every seven to ten days works if you shower before bed and don't sweat heavily.
- Wash more often — every five days — if you sweat at night, sleep naked, share the bed with pets, or live in heat and humidity.
- Sheets collect dead skin, sweat, dust mites, and bacteria that can trigger skin and respiratory problems if left too long.
- Hot water kills more dust mites and bacteria than cold, but check your sheet label first because some fabrics shrink or fade in heat.
Factors that mean you should wash more often
Night sweats are the biggest reason to wash sheets more frequently. If you wake up damp or your sheets feel wet, wash every five to seven days instead of ten. The same applies if you sleep naked — there is more direct skin contact with the sheet surface, so bacteria and dead skin accumulate faster.
Pets in bed are another factor. Dogs and cats shed fur, carry bacteria on their paws, and may have accidents. If your pet sleeps on the bed regularly, wash sheets twice a week. If you have allergies or asthma and your pet is a trigger, washing more often can reduce the amount of dander and hair that builds up.
Climate matters too. In warm, humid places, moisture on sheets creates ideal conditions for mold, mildew, and dust mites to multiply. If you live somewhere hot or humid, or if it is summer, wash every five to seven days rather than waiting ten. In cold, dry climates, you can often stretch closer to two weeks without problems, though once a week is still the safer default.
When you can safely wait longer between washes
If you shower or bathe before bed, you reduce the amount of sweat and bacteria you bring to the sheets. In that case, every ten days is reasonable. If you also sleep in pajamas rather than naked, wear a sleep shirt, or use a mattress protector under the fitted sheet, you create a barrier between your body and the sheet itself, which slows buildup.
If you spend most nights away from home — traveling for work, staying with a partner, or sleeping elsewhere — your sheets get less use. In that case, washing every two weeks may be acceptable, though once a week is still preferable if you are home most nights.
Some people also use a duvet cover or top sheet as a barrier between themselves and the main sheet. If you wash the top sheet or duvet cover weekly but only wash the fitted sheet every two weeks, that is a reasonable compromise, though the fitted sheet still collects sweat and skin cells where your body makes contact.
How to wash sheets to kill bacteria and dust mites
Hot water — 130°F (54°C) or hotter — kills more dust mites and bacteria than cold or warm water. Check your sheet label first, because some cotton blends, linen, or specialty fabrics will shrink or fade in hot water. If the label says warm or cold, follow it; a sheet that shrinks is worse than one washed in cooler water.
Use a regular laundry detergent. You do not need special "antibacterial" detergent — standard detergent plus hot water and agitation does the job. Dry on high heat if the label allows, because heat also kills dust mites. If you air-dry, make sure sheets are completely dry before putting them back on the bed, because damp sheets encourage mold and mildew growth.
Wash sheets separately from other laundry if possible, or at least wash them with similar colors and weights. Washing with heavy items like jeans can damage sheet fibers over time. If you have a large household or multiple beds, you might wash sheets from different beds on different days so you are not doing all laundry at once.
What happens if you wait too long between washes
Beyond two weeks, dust mite populations and bacterial colonies grow large enough to cause visible and physical problems. The most common is acne or skin irritation on the face, neck, chest, and back — anywhere the sheet makes contact. This is sometimes called "acne mechanica" and happens because bacteria on the sheet rub into your pores.
People with eczema or sensitive skin often see flare-ups when sheets are not washed frequently enough. Dust mite droppings are a common allergen, so if you have asthma or allergies, unwashed sheets can trigger nighttime congestion, coughing, or wheezing. Some people also notice a musty or stale smell in the bedroom, which is a sign that mold or mildew is beginning to grow.
If you have been sick — with a cold, flu, or skin infection — wash sheets immediately after you recover, and again a few days later. Bacteria and viruses can live on fabric for hours or days, so washing breaks the cycle if someone else uses the bed.
Pillowcases need more frequent washing than sheets
Your face spends eight hours a night pressed against a pillowcase, so it collects more oil, bacteria, and dead skin than the rest of the sheet. If you are prone to acne or have sensitive skin, wash pillowcases twice a week — every three to four days — even if you wash the rest of the sheets weekly. Some people wash pillowcases separately for this reason.
If you use the same pillowcase for multiple nights without washing, bacteria from your face transfer to the pillow itself. Over time, the pillow becomes a reservoir of bacteria and dust mites. Washing the pillowcase frequently slows that process, but you should also replace pillows every one to two years because they accumulate dust mites and allergens that washing alone cannot remove.
Frequently Asked Questions
Is once a week really necessary, or is it just what companies recommend to sell more detergent?
Once a week is the recommendation from sleep medicine researchers and dermatologists, not just manufacturers. Studies show that dust mite populations and bacteria grow significantly after seven days. That said, if you shower before bed, do not sweat, and live in a cool, dry place, every ten days is reasonable. The key is whether you are seeing skin problems or respiratory symptoms — if not, your frequency is probably fine.
Can I just wash pillowcases and skip the sheets?
No. Your body makes contact with the fitted sheet and flat sheet too, especially your back, legs, and lower body. Washing only pillowcases leaves bacteria and dust mites on the rest of the bed. Wash the whole set weekly, or at minimum wash pillowcases more often and sheets every ten days.
Does it matter if I use cold water instead of hot?
Cold water cleans but does not kill as many dust mites and bacteria as hot water does. If your sheet label allows hot water, use it. If the label says cold or warm only, follow the label — a sheet that shrinks is worse than one washed in cooler water. In that case, wash more frequently to compensate.
What if I do not have time to wash sheets every week?
Wash them every ten days instead, or wash pillowcases weekly and sheets every two weeks as a compromise. If you are dealing with acne, eczema, or allergies, weekly is worth the time. If you have no skin or respiratory problems, every ten to fourteen days is acceptable, though weekly is still the safer default.
Should I wash new sheets before using them?
Yes. New sheets are treated with sizing and finishes during manufacturing that can irritate skin or trap bacteria. Wash them once before the first use, then follow the weekly schedule after that.