The ducts had never been cleaned in the 47 year-old history of the house. I recently had a new heating system installed and the duct cleaning was included in the price of installation hence the zero cost. Jerry did a very professional job (spread out tarps, removed his shoes, did not spread any dust, etc.). He asked me to inspect the work upon completion and it was spotless. I have a several hundred yards long gravel driveway that goes over a swamp and up a steep hill. Incredibly, Jerry BACKED HIS RIG UP THE ENTIRE DRIVEWAY!! A very pleasant fellow, he has my highest recommendation. I had always thought that duct cleaning was a needless frill, but after seeing how dirty the ducts were and learning about the health hazards that can come from it (we have 2 fireplace inserts), I can see how important it is to keep them clean.