With DD it was about 15 months old I got rid of the bottle completely but she really wasn't ready prior. I waited until she could comprehend she was a big girl and didn't need them anymore. It was definately a comfort thing for her I still give her a cup of warm milk of a night. I use a nuby brand sippy cup. These seem to be the ones that she will drink the most water/milk out of because she has a rather petite face and the other brands were hitting her nose too much. Out of all of the cups we have tried they seem to be the easiest and the best lasting (except when the puppy gets them and chews the tops). I just throw them through the dishwasher on the top rack to keep them clean.

HTH