Oh I'm starting to think that stage will NEVER go away!
Nah just kidding. I've heard they calm down once they hit adulthood... so...a year, maybe? Yorkies will always be Yorkies but I think the rambunctiousness will eventually calm down.
I'm still waiting for Franklin to be less mischievous.... we've got 5 months to go, though!
People always tell me to enjoy the puppy stages. You should too.