The age of your baby might determine what kind of sleep-training method you choose, though. You could try a gentle shush-pat technique with a five-month-old, but you’ll likely have to leave a one-year-old in the crib as they protest (cry or scream) about the new bedtime arrangement. Don’t attempt a formal sleep-training method before four months, until your baby is able to go longer in between feeds and their circadian rhythm starts to develop. (Many babies this age still feed in the night—contrary to popular thinking, sleep training isn’t synonymous with night weaning.) Dickinson says that many four-month-old babies are biologically able to go through the night without a feed, but that doesn’t mean you shouldn’t respond and feed them if other methods of calming them aren’t working. Since every situation is different, we recommend checking with your doctor before withholding your baby’s night-time feeds.
Hogg agrees with Sears that sleep associations should be positive but disagrees with his techniques. She cautions against letting your baby depend on "props" such as nursing, patting, and rocking to get to sleep. Instead, Hogg's approach calls for going to your baby when he cries, picking him up, and putting him back down as many times as necessary.
In the first several weeks of life, babies are hungry at night, leading to an apparent reversal of day and night and erratic sleep patterns. Fortunately, this usually resolves by about 3 weeks of age, after which your child settles into a three- or four-hour cycle, typically following a pattern of waking, feeding and sleeping. At this point, exposing your baby to natural light during the day can help encourage longer periods of daytime wakefulness and more sleep at night.
"I have a 3-month-old who I rock at night. He falls asleep very quickly (much quicker than if I leave him in his crib). If he wakes in the middle of the night, we go to him and comfort him. We don't take him out – we just help soothe him. Why make him feel lonely and abandoned? I have no problem losing a little sleep if it means that he feels like we will be there for him."
Most sleep coaches say the ideal time to start sleep training (or promote independent sleep, not necessarily using the cry-it-out method) is based on your baby’s development, but is usually somewhere between four and six months, when your baby hasn’t had much time to get used to nursing or rocking to sleep. At this stage, most babies are also developmentally ready to learn the skill of falling asleep on their own, explains Jennifer Garden, an occupational therapist who runs Sleepdreams in Vancouver. Around four months of age, some babies go through a sleep regression because their sleep cycles change and there are longer periods of lighter sleep per cycle. “It’s a great time to work on independent sleep skills,” says McGinn. Other babies’ slumber derails around this time because they are working on new skills, like moving around and rolling. Some parents choose to wait until things settle down before embarking on a sleep-training method, but you don’t have to, says McGinn.