I don't remember exactly when I switched over to positive reinforcement. I think maybe that's still happening.
I know that I used old school/compulsion methods on my first two family dogs. Heck, I even remember kneeing them in the chest and rubbing their nose in poo.
Ever since I was little, I wanted to be an animal trainer. No joke. I still have the drawing of me as a zoo animal trainer I did when I was in 1st grade. After trying dog-training with those first two dogs, I didn't have a desire to train anymore. See, training wasn't fun...and it wasn't super effective either.
I got my first job as a teenager working for a large kennel. I remember hearing the staff talk about needing to do an alpha rollover on their dogs. I remember telling someone (and being quite proud that I knew this) that humping was "a dominance thing." I remember the facility trainer being completely unable to handle dogs without using a choke collar (and often lifting them off their front feet). She was hailed as a good trainer I and remember thinking that if training required so much physical strength, I probably wouldn't be a good trainer.
It was a ton of work, but it was soooo much easier than I thought it would be! Demyx was happier than most of the puppies I saw being trained. He seemed to enjoy it, and it actually seemed to make him want to be around me more. He didn't view training as a chore and neither did I.
It was time to swallow my pride and let go of all of the training knowledge I had stored up. It hadn't helped me much anyways, but it still hurt that I was wrong. That I had wasted so much time and effort training that way...that until Demyx, I had failed as a trainer. Heck, I still made plenty of mistakes with Demyx and I had to fix my mistakes later, but at that point, I knew what I had done wrong and how to fix it.
I'm still learning (10 years later) about dog behavior, what training works best with each personality, how to engage work and play drives with different breeds, and how to make training fun for owners so they actually WANT to train their dogs. Each year I get a little better and I'm still amazed at some of the complete behavioral turn-arounds many of the dogs I work with are able to achieve in such a short time. I'm amazed that I can often get the same results I see on TV, sometimes in just minutes, that used to take me months of work. I'm amazed how quickly our dogs learn that training is fun and that WE are fun to be around!
There are other effective ways to train. I'm not knocking those. For the record, there are several things I LOVE about Cesar Millan's training and I think he's really a sweetheart and I've love to meet him one day. I have trainer friends who think that positive reinforcement is garbage. That's fine! I just didn't enjoy training (and didn't have much success with it) till I found a way to train that was fun for me and fun for my dog. When I end a training session and Demyx (or a client dog) comes over to me excited to do more, it's one of the best feelings in the world.