I weaned my daughter at 1 yr- she was a great nurser but I slowly dropped a feeding every few weeks and replaced it with a sippy if she needed. I personally could not keep nursing much past that- I would not want a child much older than that to still nurse as then they're able to demand it and I wouldn't be comfortable anymore. I see it as its for babies- any older than 1 year and they should be on table food and whole milk. Those are the recommendations, right?
I have no problem when others nurse longer but I do think that by 2 it is then simply an emotional attachment. It's good to be attached, obviously, but I replaced that attachment with more cuddles and snuggles. My son is now 9 mos so we will see how it goes with #2.