A baby's teeth start coming in around 6 months. This is usually when a person would provide their baby with a teether.
Teethers are available to purchase for ages 0 months and up. If someone notices their baby starting to suck on objects, they could be trying to soothe their gums. In this instance, it could be beneficial to give the baby a teether.
A person should speak to a pediatrician for advice on teething products.