Sleep — or lack of it — is probably the most-discussed aspect of baby care. As new parents quickly discover, the quality and quantity of their baby’s sleep affects the well-being of everyone in the household. And sleep struggles rarely end when child moves from a crib to a bed. Instead of cries, it’s pleas or refusals; instead of a 3 a.m. feeding, it’s a nightmare or request for water.

So how do you get kids to bed through the cries, screams, and avoidance tactics? How should you respond when you’re awakened in the middle of the night? And how much sleep is enough for your kids?

How Much Is Enough?

Sleep quantity needs vary based on age. But common “rules” about how many hours of sleep an infant or a 2-year-old need might not be helpful when it comes to your own child. These numbers are simply averages reported for large groups of kids of particular ages.

There’s no magical number of hours all kids need in a certain age group. Two-year-old Lilly might sleep for 12 hours, while 2-year-old Marcus is just as alert the next day after sleeping for only 9 hours.

Still, sleep is very important to kids’ well-being. The link between a lack of sleep and a child’s behavior isn’t always obvious. When adults are tired, they can be grumpy or lack energy, but kids can become hyper, disagreeable, and have extreme changes in behavior.

Here are some approximate numbers based on age, with age-appropriate tips to help you get your child to sleep.

Babies (Up to 6 Months)

Newborns’ internal clocks aren’t fully developed. They sleep up to 18 hours a day, divided about equally between night and day. Newborns should be wakened every 3 to 4 hours until they have good weight gain, usually within the first few weeks. After that, it’s OK if a baby sleeps for longer periods.

After those first weeks, infants may sleep for as long as 4 or 5 hours at a time — this is about how long their small bellies can go between feedings. If babies do sleep a good stretch at night, they may want to nurse or get the bottle more often during the day.

Just when parents feel that sleeping through the night is a far-off dream, their baby usually begins to sleep longer stretches at night. At 3 months, a baby averages about 14 hours of sleep total, with 8 to 9 hours at night (usually with an interruption or two) and two or three daytime naps.

It’s important to know that babies can cry and make all sorts of other noises during light sleep. Even if they do wake up in the night, they may only be awake for a few minutes before falling asleep again on their own.

But if a baby under 6 months old continues to cry, it’s time to respond. Your baby may be truly uncomfortable: hungry, wet, cold, or even sick. But routine nighttime awakenings for changing and feeding should be as quick and quiet as possible. Don’t provide any unnecessary stimulation, such as talking, playing, turning on the lights, or using a bright mobile device while waiting for your child to sleep. Encourage the idea that nighttime is for sleeping. You have to teach this because your baby doesn’t care what time it is as long as his or her needs are met.

Ideally, place your baby in the crib before he or she falls asleep. It’s not too early to establish a simple bedtime routine. Any soothing activities (bathing, reading, singing) done consistently and in the same order each night can be part of the routine. Your baby will associate them with sleeping and they’ll help him or her wind down.

The goal is for babies to fall asleep by themselves and learn to soothe themselves and go back to sleep if they should wake up in the middle of the night.

6 to 12 Months

At 6 months, babies still need an average of 14 hours of sleep a day, with 2 to 3 daytime naps, lasting anywhere from 2 hours to 30 minutes each. Some babies, particularly those who are breastfed, may still wake at night. But most no longer need a middle-of-the-night feeding.

If your baby wakes in the middle of the night, but you don’t think it’s due to hunger, wait a few minutes before going to your baby. Sometimes, babies just need a few minutes to settle down on their down. Those who don’t settle should be comforted without being picked up (talk softly to your baby, rub the back), then left to settle down again  — unless they are sick. Sick babies need to be picked up and cared for. If your baby doesn’t seem sick and continues to cry, you can wait a little longer, then repeat the short crib-side visit.

Between 6 and 12 months, separation anxiety, a normal part of development, comes into play. But the rules at night are the same through a baby’s first birthday: Try not to pick up your baby, turn on the lights, sing, talk, play, or feed your child. All of these activities do not allow your baby to learn to fall asleep on his or her own and encourage more awakenings.

Toddlers

From ages 1 to 3, most toddlers sleep about 12 to 14 hours over a 24-hour period. Separation anxiety, or just wanting to be up with mom and dad (and not miss anything), can motivate a child to stay awake. So can the simple toddler style of always saying “No!”

It’s important to set regular bedtimes and naptimes, and to stick to them. Parents sometimes make the mistake of thinking that keeping kids up will make them sleepier at bedtime. But the truth is that kids can have a harder time sleeping if they’re overtired. Though most toddlers take 1- to 3-hour naps during the day, you don’t have to force your child to nap. But it’s important to schedule some quiet time, even if your toddler chooses not to sleep.

Establish a bedtime routine to help kids relax and get ready for sleep. For a toddler, the routine might be 5-30 minutes long and include calming activities such as reading a story, bathing, and listening to soft music.

Whatever the nightly ritual is, your toddler will probably insist that it be the same every night. Just don’t allow rituals to become too long or complicated. Whenever possible, let your toddler make bedtime choices within the routine: which pajamas to wear, which stuffed animal to take to bed, what music to play. This gives your little one a sense of control.

Even the best sleepers give parents an occasional wake-up call. Teething can awaken a toddler and so can dreams. Active dreaming begins at this age, and for very young children dreams can be pretty alarming. Nightmares are particularly frightening to a toddler, who can’t distinguish imagination from reality. (So carefully select what TV programs, if any, your toddler sees before bedtime.)

Comfort and hold your child at these times. Let your toddler talk about the dream if he or she wants to, and stay until your child is calm. Then encourage your child to go back to sleep as soon as possible.

Preschoolers

Preschoolers sleep about 11 to 12 hours per night. Those who get enough rest at night may no longer need a daytime nap. Instead, they may benefit from some quiet time in the afternoon.

Most nursery schools and kindergartens have quiet periods when the kids lie on mats or just rest. As kids give up their naps, they may go to bed at night earlier than they did as toddlers.

School-Age Kids and Preteens

School-age kids need 10 to 11 hours of sleep a night. Bedtime problems can start at this age for a variety of reasons. Homework, sports and after-school activities, computers, TVs, mobile devices, and hectic family schedules all can contribute to kids not getting the sleep they need.

Sleep-deprived kids can become hyper or irritable, and may have a hard time paying attention in school.

It’s still important to have a consistent bedtime, especially on school nights. Leave enough technology-free time before bed to allow your child to unwind before lights-out. A good rule of thumb is switching off the electronics at least an hour before bed and keeping TVs, computers, and mobile devices out of kids’ bedrooms.

Teens

Teens need about 9 hours of sleep per night, but many don’t get it. Early school start times on top of schedules packed with school, homework, friends, and activities mean that many are chronically sleep deprived.

Sleep deprivation adds up over time, so an hour less per night is like a full night without sleep by the end of the week. Among other things, a lack of sleep can lead to:

• being less attentive
• inconsistent performance
• short-term memory loss
• delayed response time

This can lead to anger problems, trouble in school (academically and with teachers and peers), the use of stimulants like caffeine or energy drinks to feel more awake, and car crashes due to delayed response times or falling asleep at the wheel.

Teens also undergo a change in their sleep patterns — their bodies want to stay up late and wake up later, which often leads to them trying to catch up on sleep during the weekend. But this irregularity can make getting to sleep at a reasonable hour during the week even harder.

Ideally, a teen should try to go to bed at the same time every night and wake up at the same time every morning, allowing for at least 9 hours of sleep.

Bedtime Routines

No matter what your child’s age, establish a bedtime routine that encourages good sleep habits. These tips can help kids ease into a good night’s sleep:

• Stick to a bedtime, and give your kids a heads-up 30 minutes and then 10 minutes beforehand.
• Include a winding-down period in the routine.
• Encourage older kids and teens to set and maintain a bedtime that allows for the full hours of sleep needed at their age.