There is a common saying that reflects a very common belief, and that is, "You can't teach an old dog new tricks."
Well, I'm here to tell you that isn't true. I used to believe it myself, but I learned differently by personal experience.
Many years ago, I had a roommate who had an old dog -- a small poodle named Benji. Benji was almost blind, due to cataracts, and very nearly deaf as well. He was 13. And he had absolutely no manners. He'd never been taught to do anything.
Oh, he was a loving pooch whose mission in life seemed to be to please everyone, but he was prone to emotional outbursts and excitement because he had never learned how to behave as an obedient dog. He was "outta control!"
I found it rather annoying and set out to teach this little brat some manners. My roommate said it was useless and that I would give up right away, once I saw how pointless it was going to be.
Well, within 2 weeks, I had that dog responding to five basic commands, all with hand signals because he couldn't hear well.
He learned to sit, stay, roll over, lie down and shake "hands," though not in that order.
My roommate was absolutely astonished, and to be honest, so was I!
If you want to know how I taught him to do these things so quickly, you need to get my free report, How I Taught An Old Dog New Tricks.
I have to admit something, too, that surprises everyone, including me: I have no training in how to train a dog.
This is why I say, train your own dog at home... it's not too hard... Well... usually not. Some dogs do require different methods, and a lot depends on the traits of the dog and its breed, and you still may need to consult a pro and/or read some books. And to help you out, I'll be looking for and recommending books as I find them.
What I did was based on two things: common sense, with an understanding of the dog's specific personal needs, and persistence (and probably suspension of the belief that it couldn't be done).
Benji died in his sleep one night, but he was a happy dog. He had found order and purpose in his life... something many of us hope for, too.