I started to wean DS from formula at 9 mths (quater milk to 3 quarters formula) then wen up from there untill he was completley on cows milk at 11.5mths but he was also having three propper meals a day and snacks he had about three bottle a day if my memory serves me and only when he was in bed!! but its up to you and what you feel comfortable with!! he use to ahve water or juice duringthe day!!