B.C.
I don't think kids ween themselves, I have seen some kids 4 year old with a bottle which in my opinion is ridiculous and lazy on the parents part. We had a hard time weening our twins off the bottle also. They were about two. I actually think it was after their 2nd birthday. We put chocalate milk in their sippy cups and let them have that for bed (they only had whole milk in the bottles) One of the boys took it the first night and was fine but the other one protested a couple of nights and we just kept telling him that the bottle was gone bye bye and that he could have his sippy with chocalate milk, by the third night he obliged and we haven't had any problems since. Good Luck I know it is hard.