I really, heartily disagree. I think it causes more stress for everyone involved TBH.

I went to a sleep school that employed this technique (but never called it that or I wouldn't have gone), and it was just awful. It wasn't helping my boy and I just had to accept he would never be easy to settle.

It got better after a looong while, but that's just the way DS is.

DD has started not wanting to sleep about 18 months, she was always pretty good before then. On advice from a MCHN I now sit next to her cot, in her room. I just sit there until she has either gone to sleep or is happy to say goodnight. The time gets shorter and shorter.
This probably wont help you much (sorry), but after three kids I feel you just have to give them the attention they need until they feel safe or secure enough to drift off on their own. All kids are different but I think you get further in the long run if you do it that way.

xoxoxo Good luck, this too shall pass.