Wean Early. Sooner is better when it comes to weaning from a pacifier. The longer it stays, the harder it is to take away. And the longer it stays, the greater the risk of speech delay, cavities, needing braces... I tell parents, "sometimes, the only way to get rid of the pacifier is to get rid of the pacifier." throwing it away may seem hard in the short run, but it's far easier in the long run.
Under one year. You don't want your baby to develop an emotional need for the pacifier that may make it difficult for them to give it up later. Kids who need a pacifier by the time they are in preschool were not given the opportunity to pacifiy themselves by some other means when they were babies.
Until they let it go. Some kids will separate from a pacifier easily as they find other things to comfort them, others are very attached. Abrupt removal from an attached kid is cruel & can have long term trust and emotional impact.Parents need to be creative in offering alternatives or gradual reduction in use untill the child gives it up on their own.