All puppies, whether they are intended to become service dogs, other working dogs, or pets, should be socialized.
Socialization involves introducing the puppy to new people and animals. Socialization should be carefully planned so that the pup experiences nothing that scares him. He should meet people of all ages, including children. He should meet people of as many different ethnicities as possible.
He should not meet strange dogs until his veterinarian says he is sufficiently immunized. Even then he should meet only puppies his age and very calm adults known to enjoy and not just tolerate puppies. The puppy should never be permitted to pester adult dogs. The best place to meet similar puppies is in a puppy kindergarten class.
He should also meet other domesticated animals, like cats, pet birds, and rodents, and farm animals if available.
A sample socialization schedule is available online. Please note that on this schedule puppies only enter public accommodations on field trips, with other puppies and under the supervision of program trainers.
The puppy should not be taken out for socialization or habituation in any situation where the trainer is not in control of what the pup will encounter and can give the pup the trainer's undivided attention. Pups should not be taken to work or school during primary socialization.
Some programs encourage their puppy raisers to take their puppies everywhere. These programs experience a very high failure rate. Carefully planned and supervised socialization results in a greater success rate.