I have a puppy dog that is 8.5 months old and he is 21.5" and very accurately measured.

Has anyone had any experiences with keeping a male that seems smaller that did grow or didn't grow? At what age would you stop holding out hope that he would grow more? Just trying to feel the situation out.

Thank you list

He should still grow more. I have a male puppy on the lower side of the standard and he had a growth spirt at 10 months and now at 11 months he looks like he is growing some more. I would give it more time. He could keep growing until 13 months.

He could grow more, but may not.

What is behind him as far as size goes? Do his lines take a while to mature? I'd definitely run on him if you like him otherwise. :)

He only needs to grow one more inch and is just 8 months old. I don't know what you are worried about. Personally I really like the lower end of the standard.

Maybe I"ve gradually grown to love the " Low Rider Labradors " which I refer to as the English style. I used to think they resembled Pot Belly Pigs but that was when I had only been around field labradors. Now I think Labradors who are 24 inches tall and all legs looks fieldish.
As far as height goes, I've seen our dogs grow in height after they turn 12 months old. We have a cute little girl now who is on the short side at just 12 months old but we are watching her height and enjoying her grow up.