If you get a long coated dog it is essential to ensure that your dog is properly groomed. So if you are considering getting a dog with long fur you must ensure that you budget for the costs related to grooming him. Failure to manage the coat can lead to dogs becoming fearful of being handled, groomed or touched. It can also lead to sores developing which can be difficult to see due to long fur concealing this. Long coated dogs require daily grooming by the owner and also occasional professional grooming.
You must ensure that you are happy that the groomer will handle your dog sensitively. Many dogs find the environment very challenging if there are a lot of dogs being groomed, lots of noisy driers and if there is a lot of barking. It is certainly unacceptable for a groomer to shout at a dog that is struggling to cope with being groomed (It does happen, I have seen and heard this personally).
As with classes, if you hear a lot of barking or distressing noises coming from dogs when being groomed this may indicate the dogs are not being well cared for. You should ask to observe dogs being groomed before you decide to let them groom your own dog. You may find a smaller groomer could be a better environment for your dog to be groomed in.
However, as with all professions, those who aspire to be the best will take professional qualifications as well as gain plenty of practical hands on experience. The City and Guilds can award various qualifications in dog grooming and cover different levels showing higher standards. So, you will want to know in detail what qualifications your groomer has. Did they just do a short course or have they worked under supervision for a longer period of time? Generally it takes several years for a dog groomer to be proficient at their job and to have gained the experience necessary to know how to do the specific cuts for breeds and also how to handle the more sensitive or aggressive dogs. There is also the British Dog Groomers Association which lists qualified dog groomers. It is not, in my opinion, acceptable for a dog to endure being groomed by being muzzled and restrained. This will brew other problems for the future and is likely to cause the dog to be unable to be handled.
Good groomers will let you observe your dog being groomed and will encourage you to take your dog from puppy hood for short introductory visits. They should also be able to guide you how to prepare your dog for grooming. Your dog should not refuse to go in to the groomers and should appear content when they come out.