If only I had known when I was at college that I needed hypoallergenic covers for my pillows, mattresses, Hepa air filter machine, as I had bad allergy to house dust mite residue. But that was the 1970s, Hepa air filter machines, covers for pillows, mattresses weren't available then. Didn't know about this from allergy doctors until 1980s. Now, I have covers on all my pillows, mattresses, hepa air filter machine in my bedroom & 1 in my studio where I work. Worth the costs as I get a good...