Hi. I have two adorable yorkies (aren't they all?). They are six years old, both females and littermates. They get along great, follow me or my husband all around, and do everything together. One weighs 8 lbs., and my other one is 18 lbs! I think that's a record for yorkies! My big one, Chewy, had valley fever and was very sick. So, we had to force feed her (baby food thru a syringe). We should've stopped when she started gaining her weight back, but we didn't because we were so worried about her. Now, we put her on a diet. That darn valley fever cost us a lot of heartaches. But now she's on the mend.
Anyway, I think they get along great and two are definitely better than one. I am gone for long hours every day, and my husband is too. So, we don't feel as bad when we know they'll be together. They still pay a lot of attention to us.