This is such a difficult subject, because it is so hard to get it right. It never worked for me, and as I result, I felt that 50% of the time I was sleep depraved, and feeling very not with it. How can you be when you are always tired. I tried the controlled crying buy my daughter could cry for hours, literally. It was amazing how much energy she had. I thought she would get ill if she continued, but she was so head strong, and just did not give up. After a couple of hours of going back and forth, I gave in to her. This went on for ages. I really think it depends on the child. I suffered so many years, with it. And then when she started sleeping through the night, I got pregnant again....and it all started up again. DD no 2 was just the same. So it was really hard. Sadly this went on for year,s and then I go insommia. But the good news is I am better now.