To a professional dog groomer, thinning shears are their "go to" tool. Yet at the same time, most people who groom their own dogs at home tend to shy away from them. In general, this is because they just don't know how to use this particular type of shear. Dog thinning shears are specially designed to only remove a small amount of hair with each cut. When used properly, they can take blunt lines between layers or from clipper cut hair to shear cut hair much softer, creating in a more natural flow. Be sure you buy good quality shears, as cheap ones won't stay sharp for very long.
While it might not seem like it, your dog loves having a nice clean well-groomed coat. From your point of view, cutting your pup's coat gives you a golden opportunity to go over his body from tip to tail looking for fleas, tick, injuries, mats, and overall skin condition. At the same time, your dog may be nervous about the shears and you using them at first, be sure to take plenty of time to let him get used to the tool. This will save you a lot of aggravation later on.
Why on earth would you want to pay the high price of taking your pup to a professional groomer when with a little practice you can do the same job and pocket all the money you have been shelling out each month? Just remember to be calm and patient, your dog will take his cues from you, making it much easier to get the job done.