The ideal time to bring a puppy home is between 8-12 weeks old, once they have been full weaned and have developed adequate independence.
When puppies go home they will still be uncertain of the sudden change in environment, new smells, and new routines. It's important to be patient and consistent; give your puppy time to adjust to it's new lifestyle. On average, it takes 2 weeks to START to adjust to their new routine. Remember, they're just babies and need structure and support.