Ok ...About 15 years ago,I held a "class on training your retriever " . had about 9 or 10 people in the first class. I do a Carr based program. After the orientation and demos in the first class,I could see that this was not going to be good.6 showed up for the second class.As it progressed,I started getting phone calls at night asking me why fido is doing this and that and what to do.Ok so I'm trying to comprehend what their dog is actually doing and trying to train over the phone.The homework is the biggest hurdle because the student has not learned how to read the dog,and some start to get mad and frustrated.Long story short ,the last three standing left me the dog and they ended up being very happy. Most trainers use the same type program,and it does not lend itself to being implemented easily by the inexperienced.Nowadays there are programs that one can get via videos and such that are broken down to do yourself ,and I guess they work.I hope this helps by having a perspective from a been there done it helperson .