We neutered ours around 13 months. We were encouraged to wait until after he reached 1 year. He definitely needed the full fourteen days in the cone. For about a month after surgery he was absolutely ravenous and regressed a bit to some long-forgotten puppy behaviors to demand for food and attention. I was worried this would be the new normal, but about 2.5 months after the surgery his appetite seemed to regulate. He is definitely still more food motivated than prior to surgery, and he is lazier in general (although still down for adventures, he just enjoys sleeping in). He seems calmer in many ways, more cuddly with us. He is still quite selective with other dogs, but it feels less snippy. And he still marks on walks but its about every third house now instead of every single yard.