We adopted a yorkie from United Yorkie Rescue about 6 wks ago. She is 5 years old. We did know she was turned in to rescue because of "aggression" issues. How long she was in the household before rescue I don't know and where she came from before that I don't know. She was not house broken and before she came to us, I don't think she pottied on grass because she did not like grass and really resisted going out there and really did not understand in the beginning what we expected from her. It took about a week and a 1/2 for her to figure it out, and she will now go outside, but I am not convinced that is the ONLY place she will go. She has had a couple of potty mistakes in the house, but we do everything we can to minimize them and we don't give her a chance to ask to go out, yet.
We are housebreaking her like she was a puppy, or like we did Millie. We are crate training and using an x-pen and keeping her confined in rooms that we are in instead of letting her out all over the house. NO pee pads, only outside potty. However, because she is older, we trust her more to "not go" if we have just taken her out. She does not have to go out as often as a puppy and she is not to active that keeping an eye on her is not so stressful. (Those are the pluses)

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We are very much into routines with Millie so having Jazzy acclimate herself to our routines did not take anytime at all. She really likes the predictability of those routines. She especially loves to go on her walks (which I don't believe she did much, if any, before). She was shy and skittish in the beginning but her true personality comes out more and more.
We are working with her on her aggression issues and there was a few days a couple weeks ago that made me think we might have to give her up, because she was being too aggressive to Millie and to us. She was baring teeth and snapping at us. We seem to have that under control now, though.
I now really understand why rescue groups are very strict about who they let adopt their dogs. Because no matter how much I though I was "in to it" or could provide a "loving home" for a dog who really needed one, and had "yorkie" experience, I really was not prepared for the type of work and transition that a rescued dog needs. And none of those altruistic reason make a bit of difference with the reality of the situation. Thank goodness for my husband who said that we were committed to this dog now and she was ours and we were going to follow thru on our decision.
The biggest thing I keep repeating to myself is that even though she is older, she is still like a puppy and has to be trained on everything. I need to spend the time on Jazzy that I did on Millie to learn the good manners that we expect in our household. Millie is 3 years old and she did not learn overnight. Her training from puppyhood to adult hood was a process and so will Jazzy's be.
Jazzy has many fine traits (there really are a lot of good qualities in her) and she can be quite the cutie. (she is a yorkie after all). It's just that Millie is our child and while Millie is NOT the perfect dog, all her character flaws were created by us

and we are used to them.

So while Jazzy has many issues to work with, I understand that no dog is perfect and given more time in our house and more bonding moments Jazzy will be great.