From my own experience with my son, I wouldn't have felt comfortable doing it past 1 1/2 years old. He was a very intelligient infant and still a very intelligent toddler. But, I do know of people who's children are the same age as my sone, almost 2 years old now, and are still breastfeeding. I think it has a lot to do with the comfort of the mother. Otherwise, I think past the age of 3 is a little "different". Hopefully I didn't offend anyone, just my thoughts.