Once your dog has received basic training, great! You have put a lot of time into training your dog. He’s functioning at a high level. You’re having a great time taking him out and about and doing all kinds of fun things together. Your friends and neighbors are jealous. Everything looks great.
As the months go by, however, there’s a little slip here and a little blip there. Your dogs once good leash-walking skills are now “usually” good leash-walking, but sometimes he pulls towards things he really wants. Your good reliable recall is now he “usually” comes when called. Sits are a little slow but he still does them, downs are even slower. He’ll do a sit-stay for a good amount of time, but frequently gets up before he’s actually released.
Fast forward another few months. Now your dog is pulling more than he’s walking nicely, his recall can no longer be considered “good,” and you find yourself struggling for control in many situations. What’s going on here? The dog looked so good seventh months ago!
What’s going on is that for the dog whose training is not maintained, eventually it will begin to disappear. This is because of consequences. If there are negative or no consequences to a dog’s good behavior, that good behavior will start to fade away. If there are no or good consequences to a dog’s unwanted behavior, that behavior will start to increase. Of course most owners aren’t intentionally punishing the dog for things like come when called, and they’re not intentionally rewarding the dog for things like pulling on the leash and jumping on people. But for the dog, even unintentional rewards and punishments will start to have an effect as the months go by.
For example, your dog pulls very slightly on the leash as you are in a rush to get from Point A to Point B. You’re in a hurry and anyway it wasn’t a very hard pull, so you ignore it, and the dog gets to sniff ahead of you at something it wanted. To the dog, this sniffing was actually a reward for pulling, and it will probably try again tomorrow, but maybe a little harder of a pull this time. Gradually the pulling will take hold as the dominant behavior.
Or, you use your dogs brilliant recall (come when called) to collect it from the dog park. The dog comes running; you leash up and go home. The next day you call it because you have to trim its nails. The next day, you call it away from its favorite playmate. To the dog, now coming when called is not a good thing – it means either that the fun is ending or that something unpleasant is about to start. If this keeps up, the dog will get slower and slower to come when called, and will likely eventually stop doing it at all.