My DS is about 11kg and 17m old, I still wear him. We have a Kari-Me sling (like a Hug-a-Bub) and DS can sit on my side, my chest, my back, face in, face out... it works well. Often I carry him to the park then take him out and let him run. DH absolutely loves it and he gets grumpy if I don't let him carry DS.

It depends on you and your son which sling you use, I like wrap slings but others don't.

I'll stop baby wearing when DS can walk everywhere alone and wants to. I guess I'll stop soon after we stop the pushchair.