Sid is 18 months old, now. I notice a great change in her. She's less active, she sleeps more than before, she's more reactive with dogs, her possessiveness is increased until becoming aggressiveness, in many cases.
Indeed, in training she works better. Her attention is almost constant on me and even walking in the park is no more a war against runners and cyclists. Now she simply ignores.
Even if I prefer her as she's now, I hope she'll change again her way to behave with dogs and puppy...
If I consider that there's a growing period between 1,5 and 3 years (and she's in) and that she's finished her 3th heat (more than the other aussies 18months old females), I can hope in a improvement from now to the next year.