So I have two very young children, 2yr and 4yr. They have their share of squabbles but on the whole get on very well and mostly play lovely together. I realise they are both still very young, but I was curious from parents of older multiple children, at what age do you start to see the true nature of sibling friendships? Or is there no real age and the level of friendship (or otherwise) flexes and changes throughout their childhood?