After I voted, I noted that at this point 8 weeks is the most popular answer. I never let the puppies my dogs had ever go before that point. There is a lot they learn from mom and each other in those last two weeks.

Letting a puppy go at 6 weeks to a loving and experienced home will still produce a good healthy and responsible dog, but let that same pup go to an inexperienced home and it may not turn out as well. There is a lot of socialization that takes place in those two weeks that is very important. Even at 8 or 9 weeks, the food preparation is critical. When I picked Princess up at 9 weeks she came with a large bag of pre-moistened puppy food that she was accustomed to. Even though I carefully transitioned her, she had digestive problems, so I switched her back to what she had been weaned onto, and did not switch her off of that until she was over 9 months old, and then it was to the same brand, just the adult forumula.