During the first three years of human life, bladder storage capacity increases disproportionately relative to body surface area. By four years of age, most children void five to six times per day. Development of bladder control appears to be a progressive maturation whereby the child first becomes aware of bladder filling, then develops the ability to suppress voiding involuntarily, and, finally, learns to coordinate muscles necessary to void voluntarily.
These skills usually are achieved, at least during the day, by approximately four years of age. Nighttime bladder control is achieved months to years after daytime control but is not expected until five to seven years of age.