Very rarely do you have to replace these guys. If your earphone piece ever seems to go quiet on you then most likely it is just dirt that is clogging the grill between the ear piece and your ear. To fix this you need to remove the ear piece and clean out the grill from the ear piece side with a toothbrush and alcohol. Dont attempt this while the screen is on because you can either destroy the ear piece or also just clog it.
iPhone 6s 内置听筒更换
