...or 12 months, 3 years etc.
I hear/see this said quite often (along with mothers only doing it for their own benefit) but I've never really understood what people mean by it 
Do they simply mean that breastmilk is no longer enough on it's own - the child needs solids to?
Or that breastmilk has no nutritional benefits over formula milk, or ordinary cows milk?
Or that breastmilk literally contains no calories or nutrients after a certain point?