Puppies are eager to learn and, if the training sessions are fun, it's not hard to teach the basic desired behaviors. However, it does take time every day to teach new skills and reinforce ones already learned. When a puppy is brought into a home, he is constantly looking for cues about who in the home is the leader of the pack and what he can do to gain the leader's favor. If nobody exhibits the leadership qualities that a canine looks for, the puppy will take over the role. To avoid this scenario, it's very important to start formal, age-appropriate training right away.