Most people wait until they are 6 weeks,although the breasts can still change,some have a sneaky measure before 6 weeks to cheer themselves up,also curiosity sometimes does get the better of you,as when analysing your self daily you get used to the size and start to think they may not be as big as you thought they would be,thats when the sneaky measure usually surprises people,if you do have a sneaky measure before 6 weeks,there could still be some swelling,so the measure will not be accurate until all the swelling has subsided,this can take weeks,it depends on the individual honey,xxx