In this article, we will explain 5 signs to replace your contact lens. As we all know that all contact lens must be replaced frequently, even those that are perfectly maintained. If contact lenses are not replaced frequently enough, protein deposits and contamination may build up on the surface of the contact, increasing your risk of developing an eye infection. Most people use soft contacts, which are especially susceptible to deposits and contamination. Gas permeable contact lenses can last a year or longer before requiring replacement.