You might want to consider having your air ducts cleaned simply because it seems logical that air ducts will get dirty over time and should occasionally be cleaned.
While the debate about the value of periodic duct cleaning continues, no evidence suggests that such cleaning would be detrimental, provided that it is done properly.
If you think duct cleaning might be a good idea for your home, but you are not sure, call and to us. As a company that services your heating and cooling system we are a good source of advice and can provide you with complete and knowledgeable answers.