Had two, one the first, it was all you could do to keep it in the same county once of the lead, rescued at 18 months. The second was a pearl, rescued at 6 months. I think once a dog reaches 2 years or near about, it is really hard to train so younger the better. Also, rescue dogs always have a history - or they would not be rescue dogs, and you gamble what that is and how it will affect the dog, atb