Discolor Pacifier / Nipple

Pacifier cleaning replacement has become an issue. Experts suggest that Pacifier should be change after two to three months which has be sell in the mark,but there are no sign in the Pacifier which to remind parents change the Pacifier, I joined the discoloration function on the sides of pacifier. With the use of pacifier, discoloration function change color from blue to colorless and transparent, when the place of colorless and transparent moreover half the total area, it means parents should change the Pacifier.