Considerations In Puppy Parenthood

Today, after spending some time at John's, Mike declared that we were going to get a Yorkshire Terrier puppy. I didn't bat an eye, but asked him if he was ready to invest a ton of time, energy and money into a pet to which he just kind of stared at me.
Puppies of any breed require a lot of time and energy as an investment in their ability to be wellbehaved as adult dogs.
Puppies are a huge financial investment as well. Things like health care, room and board, and all the incidental equipment and costs can add up superfast.
I mean, I'm not against having a Yorkshire Terrier dog, but I want to be sure Mike isn't just being impulsive here. This is a big commitment.