D.W.
Not every child can CIO..i firmly believe this and this is why. We used CIO with our daughter at 5 months. It took exactly 2 nights of her crying for 30 minutes and it was over.
Now at 10 months we lay our girl down at 8 and she sleeps until 7 am. I cant even rock her anymore. After a bath I try to rock her a bit just to cuddle and she starts squirming-if you take her and lay her down, she rolls on her side and goes right to sleep.
She also isn't a 'needy' child. She doens't use pacifiers, I dont have to hold her alot, and she isn't whiney.
So from this I have decided that some children can handle and even look forward to going to bed on their own and some children prefer the comfort of their parents.
I think this is the only ting that explains the people who CIO and have night wakings for months later and the ones who get through it easy peasy, If you think your child isnt ready for it, try something else. Every child is different.