I think a big part of these interminable arguments about tabs is based on people using the same words to mean different things. In the following, I'm trying to avoid espousing my personal religion here, I just thought it would be good to try and explain the various sects. Anyway.
Puppies may be placed in new homes once they are eating well on their own. However, they will be better adjusted and make better pets by staying and interacting with littermates and the Mom-dog until they are at least eight weeks old--older generally is better.
When people come to visit the puppies, the breeder should be grading the prospective owner at the same time the prospective owner is grading the breeder and puppies. The puppies should be ready to go to their new homes at 7-8 weeks of age.