We get this question all the time. And many people won't like my answer. In my opinion, the answer is you won't ever be done -- dogs are works in progress their whole lives. But that's not what most people want to hear. Most people want their dog to learn how to live with their family, potty in appropriate places, and have nice manners. Then they want to be done with training the dog. The truth is, if you aren't training your dog, your dog is training you!
Dogs need to be challenged and stimulated, and have consistency and know their boundaries always. Dogs need and deserve a commitment from their families for their entire lives.
During the course of every training class, every private session, every communication with students, I emphasize the need to continue working with their dogs. No, it's not the more intense training like when you are training a new behavior or a new dog, but it's what I term "lifestyle training" -- integrating training exercises into your normal everyday life and routine. I try to get this idea across to them because I want the benefits of their training sessions with us to be life-long! You can train and teach and work with your dog during mealtimes, when you are watching tv, when you are out walking, when you are riding in the car, when you are working in your yard, when you are going up and down steps, etc.!!! Once you start doing this, training and maintaining consistency becomes very easy and second nature.
Let's say you completed a great training class with your dog and then you got a new account at work to deal with. Your time at home is limited and distracted. You feel sorry for the dog you are now spending less time with and you start to "ease up" on some of the things that were working when you were in class -- say, having your dog sit and wait while you prepare his meal. Now your dog is jumping up on you, the counter, the fridge, and whoever is in the kitchen at meal time because you didn't take the 1 second to remain consistent with your dog. So your dog, in his excitement both over dinner and over you, has developed new behaviors that still lead to dinner and attention from you, but are annoying and frustrating and possibly dangerous. Now, to eliminate these new behaviors, you have some work to do! If you had decided that certain things were going to remain consistent in your dog's life and you had taken that 1 second at each meal to remind your dog to sit and wait, you would not have to go through the annoyance of reminding your dog what is good and right and expected of him. Being consistent with your dog is a far better gift to him than relaxing the rules when you feel guilty!
Keep training and enjoying the journey with your dogs!!!