I'm a strong believer in letting babies cry it out (CIO) and learn to self-soothe.
I feel like parents who don't believe in CIO couldn't possibly have ever tried it in earnest. Here's how it works, in my experience:
--On the first night, the baby throws a shitfit, screaming and getting really upset while you huddle in a corner, feeling like a horrible parent. It lasts, like, 45 minutes.
--On the second night, the baby cries for about 15 minutes.
--On all subsequent nights, when you put the baby down to sleep (drowsy but awake), she goes to sleep immediately.
--If the baby wakes up in the middle of the night, she will generally go right back to sleep without requiring extra comfort.
I suppose one could argue that this is a horrible thing, that I've raised a baby who is so apathetic that when she wakes up during the night, she knows nobody will come for her, and just gives up and goes back to sleep. But she cries for me in the morning when she's ready to get up for the day. And she cries for me all the time during the day. But when she's tired and in her crib, she's learned to settle down without me.
Prior to doing CIO, when I put her down in her crib not sound asleep (which is hard to manage sometimes), she'd pop up immediately, panicked and upset that I was leaving. It was awful. I felt so freaking guilty.
I knew this woman who strongly believed that it was very unhealthy to let your kid cry. Period. She said it could result in permanent hoarseness. And actually, I read an article on attachment parenting that said infant crying results in "increased heart rate and blood pressure, reduced oxygen level, elevated cerebral blood pressure, depleted energy reserves and oxygen, interrupted mother-infant interaction, brain injury, and cardiac dysfunction." Well, that's perfect, actually. Because my sleep-trained baby cries way less than one who is waking up screaming during the night multiple times.
In any case, that particular woman had a four year old daughter who cried her head off every day when she got dropped off at daycare. And at four years old, she was still waking up multiple times during the night.