Sometimes what they need when they're crying is to sleep. When we did the cio thing, we never let it escalate to a level that sounded like a freak out, but he did cry. It took about 3 nights, and it was hard, but now he goes into his crib drowsy but awake and moans and sings himself to sleep, never cries. now we know when he does cry there is something wrong, like teething, too cold, too hot. Its made the house a lot more relaxed and he is a lot better rested not waking every 2 hour for comfort from us. Its a personal decision but it has worked for us.