To all those saying that mothers force their older children to continue breastfeeding to keep them babies for longer, are 'needy', etc. ...
I mean, maybe that's the case for some? But my personal experience was nothing like that at all. Three years ago, I had a 4 year old and a 1 year old. The 4 year old was still wanting to breastfeed before bed, while I was more than ready to stop, as frankly it was a bit of a pain in the arse for me, also having then 1 year old who wanted to breastfeed a lot more often than her older sister.
I subscribed to the belief that a child would naturally wean on their own, though it didn't really seem to be happening. In the end, I developed an aversion to my older daughter breastfeeding - full on feelings of horrible, skin crawling, irrational anger (at her) while she was doing it. In the end, I just started holding it back/putting it off until she stopped asking.
Same thing happened as my 1 year old got older, so I followed the same method and she eventually stopped soon after she turned 3. My natural limit, before I start to find it grates on me seems to be about 3 years, by which point my children were mature and reasonable enough to give it up quite easily, though I am sure they would happily have continued.
I don't think that makes me needy and am glad they had it for as long as I cope reasonably cope with.