Everyone interested in breathing clean air, however there are some instances where is more important than others. If you have vermin, (mice or rats, insects etc) that are living or have lived in your ducts, you need to have them cleaned. If you have excess dust you need to have your air ducts cleaned. If any mold is visible you need to have your ducts cleaned. It also stands to reason that over time the ducts get dirty and you want to have them cleaned. As long as the job is done right, hire a competent and reliable professional like Burns Environmental.