Hello. I can tell you by my own experience that it depends alot on the dog, the way it was created and educated, just like on how old he is. When I addopted my Yorkshire Terrier, I addopted it from other owners that couldn't keep it anymore due to them changing from a house to a small appartment where the appartment owner stated they couldn't have pets living in there. He was 5 years old(human years) when I took him home and all I can tell you is that he is adorable. He got used to the new owner really quickly and now, months later, it seems like he's grown up with us since he was a baby dog. He's also very good on doing alarm job. Whenever someone passes by the door or even the windows there's no way to stop him from barking and growling. I don't regret having adopted it, but that's only my experience.
