Utility is an economic term for a person's overall well-being and satisfaction. Consumers play a role in the economy by maximizing utility, which means allocating their scarce resources, such as limited time or money, most efficiently. Utility maximization is different for every person.
You can start using it right away but it was suggested to us by our midwives to hold off until 6 weeks as pacifier use can mess with their breastfeeding latch (it's a different kind of sucking).
Why do some babies want to suck on a pacifier? Sucking is a natural instinct in babies. Some babies will suck their thumb or fingers, while other babies like to suck on a pacifier. In older children, pacifiers may be a form of security or comfort. Pacifiers can be soothing for babies. If your baby is cranky or fussy, a pacifier may help him or her calm down.