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).
At the 7 to 8 weeks' gestation, taste buds start emerging. After birth, infants show a preference for sweet tastes. A combination of sugar with a pacifier has a calming effect on newborns. Infants do not like things that have a sour flavor to it. Items that have a sour taste raise a frown on the face of the kid.