DS2 is 3 in less than a month and he still has them. We had them all over the house. I rounded up all the ones that had gone flat/started to wear out and when I counted them we had 17!! Plus the 4 new ones. They are the only way he will settle at night quickly so Im not keen to give them up just yet But Christmas will definitely be the end of it. That said though we have a 6yo that still sucks her thumb...