You spend roughly fifty hours a week in direct contact with your sheets, sweating between 200 and 700 millilitres a night and shedding skin the entire time. Bedding is the fabric in your home that gets the most sustained skin contact by a wide margin, which is why the answer is more frequent than for anything else you own.
Once a week is the standard answer and it is a good one for most people. The interesting part is the exceptions.
Who should wash more often
Every reason to go to twice weekly comes down to moisture, because moisture is what dust mites need and what lets bacteria multiply.
The rest of the bed
Duvet covers can go longer than sheets because there is usually a duvet, and often a top sheet, between you and them. The duvet and pillows themselves need washing far less often than people fear — two to four times a year — but they do need it, and most households never do it at all.
Pillows are also the item with a genuine replacement date. Squash one in half: if it does not spring back, it is no longer supporting your neck and it should be replaced regardless of how clean it is. Most pillows want replacing every one to two years.
Temperature
40C is the right routine temperature for cotton and linen. It removes oils and sweat effectively and does not wear fabric out the way a hot wash does.
60C is the dust mite threshold. Mites survive a 40C wash; they do not survive 60C. If someone in the house has a dust mite allergy, a monthly hot wash is worth the fabric wear. Otherwise, save it for illness.
What actually helps between washes
Making the bed immediately traps the night's moisture inside it. Throwing the duvet back and leaving the bed open for twenty minutes while you shower lets that moisture evaporate, and it is the single most effective free thing you can do.
- Own two sets. The main reason people skip a week is that stripping the bed and waiting for a wash cycle is a whole evening. Two sets makes it a five-minute job.
- Shower before bed rather than in the morning, particularly in summer.
- Use a top sheet. It is a washable barrier between you and a duvet cover that is harder to launder.
- Skip fabric softener on cotton and linen — it coats fibres and reduces absorbency, which is the opposite of what a sheet should do.
Sleeping hot changes the answer
If you sweat at night, everything above shifts by a factor of two, and it is worth addressing the cause as well as the symptom. Fabric makes a real difference: linen and percale cotton move moisture away, while microfibre and sateen hold it against you.
The how to sleep cooler guide covers the cheapest order to fix that in — starting with the pillowcase, because your head sheds the most heat.
The short version
- Weekly for sheets and pillowcases, for most people.
- Twice weekly if you sleep hot, share with a pet, or have allergies or acne.
- Pillowcases every two or three days if you have acne.
- Duvet covers fortnightly; duvets and pillows two to four times a year.
- 40C routinely, 60C for dust mites or illness.
- Air the bed for twenty minutes each morning before making it.
