Babies are born with an innate need to suck. Newborns rely on this "suck reflex" not only for sustenance but also to calm themselves. Young babies have no other mechanism to control their distress, they cannot have a drink, they can't ask for a blanket, they can't use their hands to control things.
Sucking provides them with a way to calm down, which is why many parents turn to this resource when they see that their little ones are in distress. Therefore, Babies will suck, if not with a pacifier, then with a thumb, finger, bottle, or breast.
If a baby needs to breastfeed more times for two hours, he is using Mom as a pacifier. In such cases, a pacifier can help satisfy the baby's non-nutritive sucking needs while giving mom a needed break.
You just have to make sure that breastfeeding is well established before introducing the pacifier. For babies who have trouble learning to breastfeed, the pacifier can teach bad habits, so it is advisable to wait 6 to 8 weeks until breastfeeding is well established.
Once the baby is an expert in breastfeeding and the supply of breast milk is established (usually within a few days), it is okay to leave the pacifier to the little one so that he can regulate his own distress and give parents a break when the little one has calmed down.
A pacifier does not have to be anything bad and less if the little one is removed before two years, since in this way his teeth do not have to suffer any type of deformation. The problem is when it is used longer and the child is older. Although children can naturally give up the pacifier at 3 or 4 years old, when they find other strategies to calm their distress.