My dog is only 1 1/2 years old. It was time for his annual check up, and I was told he had to have another rabies vaccination BY LAW. The law now states that pets must be vaccinated every three years. Not only that, but they had me convinced he needed to be on heartworm medicine year round (it's a mosquito-transmitted disease, and up here dogs really only need it April-October). So, my dog had been on it faithfully for a year, and I was told by the receptionist that he had to have a heartworm test as well. A bit of internet research and a few phone calls to more ethical vets in town has kept me from over-vaccinating my pup, saving him from all kinds of potential harm.