I'd say it depends. I think in the books, Tracy recommends waiting until your LO is on 3 solid meals -- I dropped it around 9 months with my first, 7 months with my second (she slept better without it!) and around 11 months with my third. I looked at it from the perspective that if they were still sleeping well with it, I wasn't going to mess it up. I did eventually find that I could tell they were taking less (less swallows) and nursing for shorter periods of time.