We used one for all 3 boys. I have a very strong view AGAINST CIO for babies. BUT for toddlers when you can talk to them more, reason with them, and they understand more I don't think CIO is always a bad thing. I think it really depends on the situation. It use to be with Hayden everytime he cried at night we went straight away. Now he cries when we put him to bed but stops within a couple minutes MAX and it's only because he wants to play not go to bed and he knows he really has to go to bed, he's just hoping we will let him stay up. However we do go right away if he's hurt of course, or in the middle of the night if he wakes..things like that. Ok with that said....for weaning off the paci with my older 2 when they got to a point that we felt they were done with it and no longer needed it (which was 13mo for Landon and 25mo for Casen, so really based on their personality and needs what we thought they were ready for) we explained that they were big boys now and no longer needed it, we threw them all away and they understood that...however they of course wanted it come bedtime. They cried a bit the first night especially and we just kept telling them they were big boys and didn't need them, they understood but were still upset. By the 3rd day they never asked again. Casen's we took at 25mo and at 30mo is when Hayden was born and he still was fine, never needed the baby's or anything, he fully got it just needed a little push to give it up. We will do the same with Hayden when we feel he is ready, he's 26mo now and our plan is by 2 1/2 it will be gone