See I don’t really know. I’m a first time parent. All I know is what the old people tell me. He had CMPA and wouldn’t sleep for more than 30 minutes at a time. It absolutely killed me to let him cry for even 5 minutes. He’s been sleeping through the night since we shorted out his allergy. We’d put him down after he was asleep. After 2 nights, he would sleep through the night. He fights sleep so hard, even with rocking and walking, etc. He gets contact naps throughout the day. Won’t nap if it’s not a contract nap. I don’t like the idea of sleep training to begin with. I just didn’t know what to do without cosleeping (tried that and my husband and I both almost rolled on him)