You are ready to move to the next stage (automation) when the dog anticipates the action and completes the down before you complete the lure.
Second Stage: Automation
In the automation stage, the dog learns to automatically give a specific behavior without being lured.
An example would be to say "down" before you start to lure your dog into position. The dog will learn to anticipate that the word "down" is followed by the lure and start to go down when he hears "down".
When the dog responds to the cue correctly 90% of the time, you are ready to move forward to the next stage.
Third Stage: Generalization
The generalization stage is when the dog learns that the response should be the same if the cue is given in a different way, by a different person, or in a different environment.
When the dog has a 90% success rate for Down in the family room, with his traditional trainer, it is a good time to generalize the behavior so that he doesn't only respond to specific circumstances.
When the dog responds to the cue correctly 90% of the time in a variety of situations, you are ready to move forward to the maintenance stage.
Fourth Stage: Maintenance
When your dog reaches the maintenance stage, you feel confident that he has complete understanding of the request. To maintain behaviors, it is sometimes required to go back to the beginning when the dog makes a mistake. This means to go back a few steps and make it easier for the dog. This will give you the chance to reinforce the correct response before it deteriorates further.
An example of maintenance is when your dog has been successful with his down stays for weeks. But when your friend comes to visit, your dog breaks his stay and runs and jumps on your friend. You will need to go back to the basics and build a stronger foundation.