I line breed occasionally, but usually never double back again. The closest I go is individual back to a grandparent or uncle. I have not done brother sister of father daughter, mother son. I just don't think my lines are so "precious" that such extreme tight breeding is warranted. I also go to lengths to obtain the best outcross blood I can get when I outcross. I breed toy and miniature poodles, mostly parti and chocolate and black. I don't breed for show dogs, but for coat quality, soundness, free of health defects, easy care, less hyper type of a good family dog. I know that is not a really lofty breeding goal in a lot of peoples' eyes, but I try to breed dogs that I would only wish on my own grandmother, upkeep and vet bills and grooming wise, ease of getting along with the family, easy to train, nice to look at. matt resistant coats, but still with good poodle coat that will hold a cut and not break off and leave a mess too much. I have lines I am currently phasing out because they are too "shrill" when they bark. Otherwise they are my best dogs. I just can't take the pitch and I doubt other people could eithe. They came from some of the best red lines out of Texas, but I just don't think they make the cut for "liveability" because of their voices, so they are done (almost) I still have one male that is fair in that department. He will probably produce "shrill" in future litters, but his puppies are otherwise so spectacular I overlook it. I would NEVER close breed that dog. He is always outcrossed on quiet girls.