I bf DD1 to sleep until over 2 and bf her as part of her bedtime routine until 3 1/2. I stopped because she was just not falling asleep and started mucking around. I think not long after this age she went to bed with her normal routine (brush teeth, story) but went to sleep on her own.

The transition from not bfing to sleep was spectacularly simple in our case. DD1 never complained once. And put that theory to bed!

Each child is different. But you already knew that.