Think about how you take care of your car. Sure, most people can handle the little stuff - checking and topping off fluids, keeping tires inflated to the correct pressure, changing the wiper blades. But, to keep your car operating at its best, you need an occasional tune-up from a trained professional.
Your heating and cooling system is no different. To get the most performance and longest life from your system, it's a good idea to have a professional perform routine checks in the spring and in the fall.