The pesky mites — which are part of the spider family and feed on flakes of skin that you can shed in your sleep — accumulate in any location that isn't regularly cleaned. In fact, there are probably around 1.5. million in your bed each night. And they'll leave their mark, in the form of welts on your neck, face, arms, and upper body, or problematic and tough-to-cure breathing issues. The longer you wait between washings, the harder it is to truly get rid of mites — or, even worse, bed bugs. Wash regularly, says Lu Xiong, co-founder of sustainable bedding brand Flaneur, "and remember to store linens in a cool, dry place away from moisture and light to avoid any bacterial build-up."