How often do you change your sheets?

IFLScience reports that once a week is the magic number of times to change your sheets to avoid allergic reactions to fungus and germs that can breed in our beds.

"After testing thousands of American homes, the researchers found that more than 90% of them had at least three detectable allergens," reports IFLScience. Even if you don't have allergies, the presence of these allergens in your sheets night after night can lead to sneezing and other upper respiratory problems.

IFLScience notes that humans can produce up to 26 gallons of sweat a year, and "our pillows alone can house as many as 16 species of fungus each." Ew.