I would go with an adult dog from a breeder.
The bottom line is a PSD MUST have a rock solid temperament. They, above all other service dogs, need to be flawless.
My vote is that you get an adult dog; an adult from a breeder would be the best case scenario, but an adult from a foster home and a good rescue group could also work.
My organization gets all our dogs from shelters/rescues. We do not evaluate puppies because our evaluations are not accurate on puppies. Our evaluation is not terribly accurate on adolescent dogs, either, so we try to at least judge that the dog is full-grown before we evaluate him.
The service dog shelter evaluation doesn't particularly require a lot of skill - besides being good at reading dogs and making quick decisions in an unpredictible environment - but it does require a LOT of experience. I saw and assisted in probably over 5,000 dog evaluations before I got to do my own, and even more before I finally got to pull dogs on my own without my trainer seeing the evaluation. I would not suggest someone without a LOT of experience with shelter dogs to do the shelter evaluation on their own.
As far as a puppy, like was mentioned above, you really won't know the dog's temperment or suitability to be a service dog until you've put over a year's worth of training into the dog. Even the organizations that breed dogs for their programs only have a 20-40% success rate among the litters that they raise. IMO raising a puppy as your first service dog would be setting yourself up for failure.
so it would be help if you could give them a bunch of ways to JUDGE if they have potential.
"how does he do in public places?"
"quick to learn?"
"easy to please"
"ok with other people"
"dogs?"
"loud noises?"
and of course a description about what your dog would need to know how to do
I'd HIGHLY suggest talking to some service dog organizations and/or visiting to spend some time with their dogs, to get a better idea of temperment qualities you would be looking for. For example, I personally do NOT like service dogs that learn quickly; if they learn training skills quickly, they will also learn how to get into trouble in the home. Smart dogs are difficult for our clients to live with; I'd much prefer a dog that learns slowly.
There's also a HUGE list beyond this one of qualities you'll have to look for.
I often send a long description of our selection criteria to rescue groups, which they use to determine which dogs to recommend to us. Still, about 95% of the dogs they recommend to us will not pass our evaluations. I'd imagine breeders would be the same way, unless they happen to have experience with service dogs. So I do think it'll be immensely important that you visit the dog and evaluate him yourself before deciding to bring him home.
Small dogs are typically huggers or fakers. Sure, there are some legitimate service dogs that are small, but they're rare, and so I think people will assume that a small dog isn't really a service dog, and you'll have more access disputes.
My org uses small dogs as hearing dogs. 30 pounds is our ideal - large enough to see on the floor in public places, but small enough to fit easily in restaurants, movie theaters, airplanes, etc. 15 pounds is the absolute smallest we will go, though, because they are difficult to see in a crowd.
Not that it matters, since the OP needs a tall dog; just FYI.
Also, I really, really suggest going with a program for your first SD.... I've heard Susquehanna Service Dogs is a great PSD organization.
I didn't know that Susquehanna did PSD dogs (will have to go look that up!), but I do know that they do a great job with their service dogs; I'd recommend them as well.
Also, I'm not sure about not taking the dog into public until it's a year old....I live right near an enormous guide dog foundation, work with people who work there, and often see them training in public.
Puppy walkers take those pups into public wearing a cape starting at 12 weeks old. And by four or five months those dogs are pretty rock solid in public about not being distracted, barking, etc.
I'm starting to think puppy is the way to go. I think a rescue puppy is the riskiest option, though. But also at 2 or 3 months a puppy wouldn't have had a lot of trauma or developed many negative behaviors.
Again, if you rescue you won't know the genetic history of the puppy, which is extremely important. The genetic history will help you determine not only the temperment, but also the health of the puppy; you'd hate to train him for three years only to have to retire him for HD (which, in a tall dog like you said you will need, is much more likely).
Like was mentioned, puppy raisers do usually have to have permission to take their dogs into public. Socialization is EXTREMELY important for service dog puppies, though, so if you get one you'll have to get him out into public several times a week. You can, of course, go into pet stores, hardware stores, and other places where pet dogs are allowed, so that is still an option even if you can't take the puppy into most stores.
And even guide dog puppies go through adolescence.
The "rock solid" 4-5 month old puppies you see, I assure you, do not necessarily remain rock solid when they grow to adults.
The thing with Psychdog is that it encourages "task shopping" and creating a list of tasks to try to justify a service dog, while the proper way to go about it is to think what problems you have, and then go from there deciding what a service dog can do for you.
Psychdog also encourages tasks that aren't really tasks, such as hugs, kisses, comfort, and tactile stimulation. Of course those things can all be helpful, but they're not tasks on their own.
:hail::hail: The whole "task" debate is a huge soapbox for me, so I just wanted to repeat these two statements.
Oh, and BTW:
Here, a lot of stores have a sign in the window (at least big corporate grocery stores and wal mart and costco and stuff) that say "Service dogs always welcome" and a number you can call to report if they give you a hard time.
If they won't let you in with a legitimate service dog, the number you should call is the police office. It is a misdemeanor offence, punishable by fine and/or jail time.
If you train your own service dog, one of the MOST IMPORTANT things you should do is to familiarize yourself with the state and federal laws regarding service dogs; know your rights, know what to do if your rights are violated, and stick to it.