Many people remember their parents wagging their fingers, nudging them to their bedrooms to go to sleep every night.
But in a large number of households, parents aren't pushing their kids to get enough sleep at night.
That might not sound like a big deal, but school Superintendent Lynn Moody said she thinks sleep deprivation is the No. 1 health problem in the Rock Hill district.
"Our kids are not getting eight to 10 hours of sleep, so they are ill and tired, and they get angry and they get frustrated," Moody said.
Depending on age, children need up to 12 hours of sleep a night, according to the National Heart, Lung and Blood Institute.
When children don't get enough sleep it can cause problems at school.
Children who haven't slept enough react one of two ways in school, said Sylvia Echols, co-coordinator of Central Child Development Center. They either become lethargic and are too tired to focus or they get wound up and too excited to focus.
"You either get a child who's too tired and sleepy, or you get a child who's revved up," she said.
Children who react the latter of those two ways often are misdiagnosed as having attention deficit disorder, said Helene Emsellem, a spokeswoman for the National Sleep Foundation and author of "Snooze ... or Lose!: 10 'No War' Ways to Improve Your Teen's Sleep Habits."
In reality, Emsellem said children are staying up too late and waking up too early.
"I think that we live in very much a 24/7 society right now," she said. "I think that the degree of electronic connectivity we have right now is a major factor."
Emsellem cited the constant availability of the Internet and TV programming as well as text messaging as examples of technology that can keep kids up past bedtime. Students stressing to perform well in challenging advanced courses and apply to college also is a concern for teenagers, she said.
Echols said pressure to be involved in extracurricular activities makes it hard for some parents to get their kids to bed on time.
She suggested developing a bedtime routine to help ensure children make it to bed and thus are well-rested and ready to learn in school the next day.
The earlier children learn the importance of sleep, the easier it will be, she said.