I gave ds a paci at 2 wks and I definitely used it constantly to hush my baby because he was such a "sucker", and I didn't really care what others thought because it made him happy.
Then, oneday at church when he was three months old, he woke up in the middle of the sermon and spit his paci three pews up! I was stunned. He never took a paci again, absolutely hated the thing!!! (and I didn't react or anything to scare him when he spit it, it was like he just decided he didn't like it)
Oh yea, be prepared though for fertility changes...I got my af back within weeks of him taking the paci, and the month after he rejected it and went back to using me, I lost my fertility again! haha