When the baby is 8 months old, he becomes very independent. He reaches for the bottle and insists on sipping drink on his own. Running with a bottle with teat isn't safe because the child can choke, whereas the constant use of the teat makes the child use it as a comforter. Another disadvantage is that the prolonged use of feeding teat may cause bite problems. A toddler who constantly drinks sweetened drinks from the bottle may also develop dental caries. Drinking from a cup, however, will teach him how to swallow and breath correctly while drinking.
You can start teaching your baby how to drink from a cup when he's able to sit and eat from a spoon. Some children are ready to start cup drinking already at 6 months old, while others can take as long as one year.