A toddler who is still drinking from a bottle may skip meals if she knows the bottle is available. So encourage your child to drink from a cup. When you serve water, for example, always serve it in a cup. Bottles should be phased out between 12 and 24 months of age.
Sippy cups can be used as a transition between bottles and open cups—and they can minimize spills (unless your toddler unscrews the top). When you start using a sippy cup, use it for all liquids, including milk, right away, and then switch to an open cup (such as a 2-handled cup) as soon as your child can manage it, usually before age 2. But keep in mind that your toddler only needs to drink when she’s thirsty or with meals. If you let her hold on to the cup most of the day like a security blanket, she may end up overdrinking (and need more frequent diaper changes). Also, frequently drinking milk, juices, or sodas can lead to tooth decay because teeth are continually being bathed in sugary liquids that help bacteria grow. Do not let your child go to bed with a bottle or sippy cup to drink from.