T. Stewart wrote:

How important is the generally accepted 8 weeks old timeline?

That "8 weeks timeline" is probably one of the most misunderstood
things in dogdom. It originally came from a book called "New
Knowledge of Dog Behavior" by Clarence Pfaffenberger (don't be
misled by the title; it was published in 1963). The book summarizes
some of the research findings from an experimental laboratory in
Bar Harbor, Maine. What the researchers there found was that if
puppies weren't exposed to humans by the age of 7-8 weeks, they
could never bond to humans, period. The humans don't have to be
the dog's final owners; a good breeder will take care to expose
their puppies to a variety of people and older puppies switch
allegiance to a new home without a hitch.

In other words, a well-socialized 6-month-old (or 1-year-old, or
any older puppy or adult dog, actually) is a far better bet than
a 7- or 8-week old that was raised in a barn.

And for what its' worth, for all that I adore socializing young
puppies (and I help breeders do so every chance I can) my last
four dogs came to me at the ages of 1) 5 months, 2) 1.5 years,
3) 9 months and 4) 1.5 years. I've only had dog #4 for 3 months,
but I absolutely adore him. I agreed to take him sight unseen
based on his breeder's description of him and he's even more
wonderful than I'd expected.

HTH,

Dianne