I know my friend that has the service dog got him when he was 2. He's lab and retriever, and a great dog. he was fully trained when she got him, but he still made mistakes. He is trained to take paper from the computer, and she said when he first came, he would hear the printer, and get SO excited about his JOB, he'd rip it out with out waiting...when he comes into where I work, you dont even know he's there....(til I slip him a treat, LOL)