Infants and Children. According to the Mayo Clinic, infants often sleep for up to 16 hours each day. Preschoolers should get about 11 hours of sleep each night, and children under the age of 13 should get about 10 hours of sleep a night. Teenagers should get nine hours of sleep a night. Kids Health from Nemours notes that getting enough sleep is critical for children because lack of sleep may affect their growth rate.