"A young child cannot yet understand what is best for him, and he may cry if he does not get what he wants," Ferber writes. "If he wanted to play with a sharp knife, you would not give it to him no matter how hard he cried, and you would not feel guilty or worry about psychological consequences. Poor sleep patterns are also harmful for your child and it is your job to correct them."
Honestly, in our personalized consultations, we try to avoid this method as much as possible. If you are going to use cry it out, we recommend your baby is at least 6 months old, but preferably 10 months or older, when we expect almost all babies to be able to get through the night without a feeding. It is not for the faint at heart. We find that laying a foundation in the beginning with other strategies and techniques can reduce crying even if this method is used in the end, however.
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.
There’s also no need to institute a regimented cry-it-out plan if what you’re currently doing is working for your family. But good sleep habits never hurt, and being able to fall asleep on one’s own is a necessary life skill. If you sleep-train at a time that’s developmentally appropriate for your baby and with the basic ingredients of healthy sleep in place, you can minimize the amount of crying your baby (and, let’s face it, you) will do.