When do you transit from bottle to sippy cup?

Instead of a sippy cup, you may want to consider the Reflo cup. It looks like a standard cup, but with an insert to control the flow of water so your child learns how to drink from a cup without having to do another transition from sippy cup to cup. Any child who is old enough to use a sippy cup may start using the reflo cup. http://www.reflo.net/