Most experts recommend starting when your baby is between 4 and 6 months old. By about 4 months, babies have typically started to develop a regular sleep-wake cycle and dropped most of their night feedings. These are signs they may be ready to start sleep training. Many babies this age are also developmentally able to sleep for long stretches at night.
"No Tears" Techniques: Just as some parents and experts believe that it is harmless to allow an older baby to cry for set periods of time, others prefer sleep-training methods that gradually teach the baby to fall asleep without Mom or Dad’s help. For example, one "no tears" method involves sitting in a chair next to the crib while the baby falls asleep, and then, each night, moving the chair farther from the crib until it's in the doorway—and then, finally, outside the room.
Pantley offers a gentle and gradual approach to all aspects of sleep, customized to your baby's needs. She recommends rocking and feeding your baby to the point of drowsiness before putting him down – and responding immediately if he cries. Parents are urged to keep sleep logs, nap logs, and night-waking logs. Pantley also describes a six-phase process for teaching a child to sleep in a crib.
Proponents of these sleep training methods say it's okay for your child to cry when you put him to bed and leave the room, although they don't advocate letting a baby cry indefinitely. Typically, these methods suggest putting your baby to bed when he's still awake and allowing short periods of crying punctuated by comforting (but not picking up) your child.
Do your research! There is a lot of information about there about sleep training, and much of it is controversial or contradicting. However, just like making any important decision, your choice to sleep train (or not sleep train) should be informed by your own reading, research, and inferences. Furthermore, there are many different methods of sleep training (which we’ll cover in this article as well) and you’ll need to decide which method is right for you.
If your baby is older than six months, don’t worry, McGinn says: “It’s never too late to develop good sleep habits.” Dickinson says he finds nine months to be a bit of a sweet spot for parents in terms of getting babies to sleep through the night. “They are at a good age for understanding routines and don’t need to eat during the night,” he explains.