When mixing breeds, Coren suggests getting dogs of relative sizes and activity levels. And a puppy can irritate an older dog because he wants to play all the time. Most veterinarians say the issue of care should figure in your decision to get another dog. Robert Patterson of Long Beach, California, agrees. Patterson, who breeds and owns Golden Retrievers says that they need to be brushed to keep their coats looking shiny and healthy.
Large dogs can be more difficult to manage than smaller dogs.
They also eat considerably more. The less time you have, the smaller the dog should be. Small dogs can get adequate exercise running around inside. Larger dogs require daily romps outdoors. A house with a big yard allows you to have almost any kind of dog you wish.