78 percentage of contact lens wearers who hang on to their cases longer than they should, finds a new survey

Shape, Feb, 2008

"The moist environment in a lens container is the perfect breeding ground for infection-causing bacteria and fungi," explains Louise Sclafani of the American Optometric Association. She suggests buying a new case every one to three months. "Or boil the one you have for at least 10 minutes." And remember to toss out leftover solution and leave the case open to dry after every use.