Would you prefer to buy or to adopt pets?

I know that there are a lot of people who goes for adoption. However, I prefer buying a dog from a legitimate seller. When you buy a dog, you get the necessary papers and medical records which, for me, is the most important thing. I want to make sure that my dog is really healthy before I buy it because complications would be both hard for me and the dog, as well. It would hard for me financially to buy the medications and as a result, the dog would be in pain. And I don't want those things to happen. So even though it might cost me a little bit more, I would still go for buying a dog.