Diapers are usually changed once every 2-4 hours. If your baby drinks more during the day, the diaper may be full of urine in about 2 hours, so you need to change it in time to prevent your baby’s red bottom, or bacteria breeding induced urethritis. If the baby sleeps for a long time and drinks relatively little water can be replaced once every 4 hours. The baby can be replaced about 1-2 times while sleeping. Because the baby has less bowel movements during sleep. Try to help your baby develop a good sense of bowel movements after 6 months of age.