Iv said this lots of times but here I go again..lol.I got Lady when she was 7 weeks old and she only weighed 8oz.I knew nothing about yorkies back then so I just assumed her tiny size was normal for a toy breed and I took her home feeling fine about her age,size etc.
She´s never had a single problem and has never had special treatment for being so small etc...to me she is the same as my 9lb yorkie
Right now she is 15 months old and weighs 2lb´s and as I said before,Iv never had a single problem with her.I think that taking a 7 week pup home is fine because in my case everything turned out ok.Some breeders dont let their pups go until 12 weeks,and I totally respect that.I think that the age you can take a pup home doesnt depend on the new owner,it depends on weather the breeder is willing to let it go or not.