This is the proper frequency for changing your sheets.

[MilaStone]

There aren't many things more enjoyable than settling into a cosy set of clean sheets for a restful night's sleep, but experts say there are numerous advantages to regularly washing your linens that go far beyond mere cosiness. If your bedding isn't kept clean, dust mites, which feed on dead skin and can quickly grow if your bedsheets aren't changed frequently, can breed there. It's a horrifying concept, but according to The Sleep Council, "as much as a tenth of the weight of a pillow that has never been washed is made up of human skin scales, mildew, dust mites (including dead dust mites) and their droppings." So, regardless of how frequently you wash your bedding, you might want to think about including a few additional suds sessions. The Asthma and Allergy Foundation of America advises that you change your linens at least once a week, more frequently if you have a dust mite allergy. As the Mayo Clinic notes, "Sneezing and runny nose, which are symptoms of hay fever and dust mite allergies, respectively. Many patients who have a dust mite allergy also have asthma symptoms, such as wheezing and breathing problems." If you have any of these symptoms, you should wash your linens once a week, paying close attention to the temperature of the wash cycle. Dust mites and bacteria should both be killed by water that is at least 140 degrees.