This is really interesting!
My DH had horrible allergies before we got married. Sneezed a gazillion times every morning. His sheets got washed every other week. Since we got married 15 yrs. ago his allergies are so much better. I wash the sheets every week...but the pillowcases get done every other day
because I love the smell of laundry detergent. I never put 2 and 2 together!