The primary and most important time for puppy socialization is the first three months of life. During this time puppies should be exposed to as many new people, animals, stimuli and environments as can be achieved safely and without causing over-stimulation manifested as excessive fear, withdrawal or avoidance behavior. For this reason, the American Veterinary Society of Animal Behavior believes that it should be the standard of care for puppies to receive such socialization before they are fully vaccinated.

Because the first three months are the period when sociability outweighs fear, this is the primary window of opportunity for puppies to adapt to new people, animals, and experiences. Incomplete or improper socialization during this important time can increase the risk of behavioral problems later in life including fear, avoidance, and/or aggression.

Behavioral problems are the greatest threat to the owner-dog bond. In fact, behavioral problems are the number one cause of relinquishment to shelters. Behavioral issues, not infectious diseases, are the number one cause of death for dogs under three years of age.