Police dogs begin training for a career spanning 5 to 13 years when they are 9 months to 3 years old. Patrol dogs have about 4-6 months to study obedience, agility, aggression, tracking, searching, handler protection, apprehension under gunfire, apprehension without gunfire, and recall. Detector dogs have about 2 months to learn how to distinguish scents and develop a nose for crime. Among the lessons that handlers learn when they first train with their dogs is that learning should not end after the initial training. Obedience or aggression training can happen daily after basic training. Recommendations vary from 10 to 40 hours of training per month. The type of training depends on the dog. National and regional associations are available to offer helpful suggestions for training scenarios; some offer certification programs. Maintaining good records to document what a handler has done with the dog is almost as important as the training. In addition, the most successful canine programs have a supervisor who pushes people to train the dogs.