I have been involved with detection dogs since 2001. In that time I have seen a lot of dogs, trained a lot of dogs, and taught handlers with many different breeds. I chose to work with Labrador Retrievers because of their trainability and temperament for working with handlers/trainers at all levels.
The breeding stock I have sought out, not only provides the option to breed for drive, temperament, and overall trainability, they also are highly athletic and are tireless. I strongly believe a structured foundation before 12 weeks of age gives the puppies an advantage as the go to their new homes.
My definition of an active home is where the dog will have a job or be out training or actively doing something 3-5 days a week. These are not going to be the type of dogs that will enjoy laying in front of your fireplace if you do not work/train with them.