“Crying It Out (Extinction) The optimal time to use this strategy is after three to four months of age (post–due date). Perhaps this is when both parents must return to work full-time or with postcolicky infants (colic usually starts to dissipate at three to four months) or after parents see partial success with graduated extinction. Extinction can successfully be used earlier, but most parents find it unacceptably harsh for younger babies. Extinction was used with some twins in my survey at five to six months of age after the due date, when the parents had suffered from becoming desperately sleep-deprived. At three to four months, many parents in my survey used extinction successfully. Extinction means open-ended crying at night. The process is pretty straightforward: if you know that it is time to sleep and not time to feed, you ignore the crying, without a time limit. Initially, the baby will fall asleep after wearing herself out crying, but very quickly this process teaches the baby how to fall asleep unassisted without protest or crying. And the baby then stays asleep for a longer time. A major fear here is that prolonged crying by one twin will disturb the sleeping of the other. Parents in my survey stated that the sleepy twin, surprisingly, almost always adapted to the crying after a few nights and slept through their sibling’s protests. Of course, another major fear is that you will harm your child by letting him cry. But as long as he is safely in his crib, letting him cry is only a means to an end of better sleeping. There is no published research showing that this procedure causes any harm to children. In contrast, there is no question that not sleeping well truly harms them. If your twins’ bedtime is early and naps are in place, the process of extinction usually takes three to five nights. In general, the parents in my survey describe the first night’s crying to be thirty to forty-five minutes, the second night’s ten to thirty minutes, and the third night’s zero to ten minutes. If their bedtime is too late or a twin is not napping well, the process may take much longer, or it may appear to work but the success is short-lived. Sometimes older children cry more on the second night than on the first, but the entire process still takes just a few days. “We started around three or four months as fatigue from care and unpredictable sleep schedules reached the breaking point. The first night, our babies cried for about twenty minutes; the second for about ten minutes. They’ve slept through the night ever since.”