Half the battle of dog training is finding the right training class and the right trainer to assist you along the way. Not all dog trainers or classes are created equal! There are a lot of differences among trainers, and you need to be prepared to find the best one for you and your dog.
For the health and wellbeing of your dog, training should really not ever be considered an option when owning a dog. Well trained dogs are more likely to be behaved and listen, be void of behavioral issues, be good in public, and are less likely to bite. Owners also have a much closer connection with the dog when the time is taken to form a relationship through training.
So you have made the decision to get a dog. Perhaps you had a bad experience once before with a dog who you thought was cute or friendly, but then when you got him home he turned out to be a holy terror, and the whole thing turned into a nightmare. Even if you have never had such a bad experience, the fact remains that choosing a pet is a life-changing decision, and it is one that takes a lot of thought and research.