There’s not an exact time that we can recommend, as all babies are unique and it will depend on how tired baby was, how much sleep they got that day, etc. Ou recommendation is to be sure baby falls fully asleep. You can also try working on your bedtime routine if baby is waking up fussy—white noise and dim the lights 20 min before bedtime. bath time, etc.
"My son is 6 months old and finally goes to sleep without a struggle! We thought the Ferber method was mean and that alternatives would be better. So we tried it all – Baby Whisperer, No-Cry Sleep Solution, Babywise, etc. None of it worked. Our son is an otherwise happy little guy, but every night and every nap was a battle. We'd spend hours trying to get him to sleep. We delayed trying Ferber until we'd tried everything else unsuccessfully. It worked after the first night! He wakes up better rested and happier (as do we)."
Also on the far end of the cry it out spectrum is the Baby Wise approach by pediatrician Robert Bucknam and co-author Gary Ezzo. In their book On Becoming Baby Wise, they advise against feeding babies on demand around the clock and instead advocate a parent-led feeding, wake, and sleep schedule. Their method involves following a strict nap and sleep schedule and putting your baby down awake so she can learn to soothe herself to sleep. This means there will be some crying, especially at first, as your baby adjusts to your schedule.
Whatever you decide, remember that sleep training baby is different for everyone. You’ll always hear about a baby who was able to sleep through the night from day one, but don’t expect overnight miracles. So how long does sleep training take? Experts say most strategies will take a week or longer to implement, and sticking them out is key to making them work.
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.