We gave DD a dummy when she was 2 weeks old as we were exhausted and needed to sleep! She very quickly got to the stage where she wanted it constantly and would wake up in the night crying for it (we never put her to bed with it). When she was waking up about 10/20 times a night crying for it (I had given the dummy to her but it had fallen out as she dropped off to sleep), we decided that enough was enough.
We then completely banished the dummy and within about 3/4 days, she forgot all about it (they were long days though!). We actually took a couple of long flights recently and took a dummy with us just in case she got really upset. She wasn't in the slightest bit interested in it.
We replaced the dummy with a muslin. Now, when we are doing her evening feed, we give her a muslin which she strokes her face with as she drops off. She doesn't really get to sleep without one.