Part of deciding to add a dog to your family is making the choice between a puppy or an older dog. Each stage of a dog's life has numerous advantages to the other stages, so it really boils down to what matters to you most.
The Settled Senior DogOfficially seniors by seven years of age, most dogs don't earn the "settled senior" title until they are nine years or older, especially smaller dogs that mature slower than larger breeds.
Pro: Senior dogs are wonderful, tempered animals that don't get quite as excited, or quite as anxious as young dogs. They are confident in their skin, and are happy to either walk a sedate mile with you or lounge on the sofa beside you.
Con: A senior dog may have age-related issues that could be either time-consuming (sight or hearing loss), or expensive.
Pro: Most senior have already been housetrained, evaluated for their compatibility with other animals and children, and have had additional basic training.
Con: Undesirable behaviors that have been picked throughout the dog's life may be harder to train him out of. You can teach an old dog new tricks, but undoing behavior is harder.
Con: The biggest reason that senior dogs are hard to adopt out comes from the mentality that people have when they think "why would I give my heart to a dog who is only going to die in a year or two?" Dogs wiggle into your heart rather quickly, and adopting a dog that is ten years old could mean that your relationship is of a short duration.
Pro: I admit that I have also shared the sentiment, "why adopt a dog just to watch it die"; it's hard to watch a pet you love age and die. But I've also learned that the relationship is a very rewarding one, for both me and my old dog. Even knowing that heartache could be right around the corner, I'll do it again and again after, because the joy is just so much more. And a nine-year-old may still have another four years left to live. Why not help make those years as comfortable and content as possible by giving him a lovely retirement home?
The Mature Adult
From three to six years of age, a dog has really come into himself. He knows what feels good, what tastes good and where to get what he wants. Adult dogs know how to settle into the good life with little fuss.
Pro: Adult dogs in shelters and rescues are usually mostly housetrained, if not completely, and have had basic training (sit, stay, come, etc.).
Con: It's harder to untrain a dog of certain unwanted habits, like counter-surfing, garbage-eating, etc. Luckily though, it can be done, it just takes persistence and consistency.
Pro: Most dogs have been evaluated by the volunteers for compatibility towards other animals and kids.
Con: Adult dogs have an unknown quality to them. Something completely innocuous could turn them into fear-biters or undo weeks of socialization.
Pro: A full-grown adult dog can still be puppy-like in his desire to play and run with you. Dogs of all ages love to play and a full-grown dog has fewer physical limitations on what kind of physical activity he can do.
Con: The fear that an adult dog won't bond properly with his new owners is a big one. Some breeds are notorious for being "one-man" dogs, and this puts off a lot of potential adopters.
Pro: Most adopted adult dogs know they have found a good life and are reluctant to leave it.