We are waiting to see if a recent breeding took. So all of a sudden I'm getting tons of puppy inquiries. Just yesterday I got one from someone who lives in an apartment. In her questionnaire she promises that the dog will get lots of exercise. Then, in going through the rest of the questionnaires, it turns out that everyone promises that a dog we sell to them will get lots of exercise. It's a ubiquitous assertion, and the less space people have, the more vehement they are in promising that the dog will receive adequate exercise.
So, from a breeder's perspective, it can be very difficult to determine which cave dweller really will give the puppy tons of exercise, and which are just saying what you want to hear so they can get a puppy from you. Or maybe they are truly well-intentioned and plan to give the dog adequate exercise, just as they are equally well-intentioned when they make their New Years resolutions that fall by the wayside before January is over. Also, some cave dwellers misunderstand what a dog needs. One apartment person wrote that he runs five miles a day and will take the dog with him, not understanding that repeated five-mile runs will do serious orthopedic damage to a developing adolescent dog. He had no alternative plan to exercise the puppy.
Then there is the fact that most apartment dwellers don't stay in the same apartment for 10 years or more, and when they move it is often to another apartment. A new apartment that may have new rules about pets, or that may not have access to that great place to exercise dogs that was a 5 minute walk from the previous apartment. Cave dwellers are often younger and less stable than those who have settled into owning a single family home. Their living situations are often still developing, as they move into careers and living situations and family. There is much greater long term concern about radical change for those who rent apartments than there is for those who own houses.
Thus, for myself, while I have no hard and fast rule against puppy buyers who live in apartments (and have placed puppies with cave dwellers), such situations do get extra scrutiny. I do make it a point to remember that I wasn't that stable, either, for a while. And that I raised a Golden Retriever while living aboard a sailboat, and that dog had an amazing life. She became a marine rescue dog. She swam every day. She moved with me to the Virgin Islands, where she had a pool, acres to run, and the Caribbean Sea. She moved back to California with me, where she lived in an apartment for a while, and then to a house with a pool, and finally died in a house by the beach. But not everyone is as crazy about dogs as I am, and not everyone will sacrifice career and lifestyle to care for a dog. So, living in an apartment is definitely a red flag, but is not itself determinative.