I certainly would adopt a Yorkie from a shelter if I were looking to add another Yorkie anytime soon. There was a total sweetheart of a little Yorkie boy in the Charlotte shelter earlier this month. He was adopted within two days. Small breeds, especially young ones, are adopted out pretty quickly here.
I've never adopted from a shelter, but I do have a little sweetie from a Yorkie rescue group. I made sure I had money set aside for emergencies and vet care since I don't know much about his background. Thankfully, he has been perfectly healthy since I brought him home. I have been very, very lucky.
I loved adopting an adult pup - I knew his size, coloring, and temperament before I brought him home. He is *exactly* the pup I wanted. Feisty, playful, and brave wrapped in a tiny package - all Yorkie, all the way.