Why is ductwork so pressing?

When the HVAC tech came in and did the inspection on our gas furnace, he also tested the ductwork.

He told us he had observed a couple of cracks along the seams of the ductwork. He wanted to call a team of professional ductwork cleaners and have them inspect the entire ductwork method and see if it needed repaired or upgraded? If it was able to be repaired, they would service the ductwork, then disinfect and sanitize it. I uneasy about what it was going to cost if I needed to upgrade the ductwork. I knew it had to be pretty old. The ductwork was already in the apartment when both of us bought it, nearly fifteen years earlier. I agreed to have the ductwork professionals come to the apartment and inspect the ductwork. When they arrived, I asked them why the ductwork was so pressing. They explained that the ductwork was enjoy a major highway. It is how the heating and air conditioner is directed through the entire house. When there was a crack or hole somewhere in the ductwork, there was a loss of heat or AC coming through that hole. We would be wasting energy since both of us didn’t have regular airflow, and there was a loss of energy/HVAC. I didn’t want to be losing heat or air conditioner, but I knew it would be valuable to upgrade the ductwork. I held our breath as the inspection was done. Luckily, all they had to do was seal the ductwork, and then they cleaned and sanitized it. Our ductwork was fantastic for at least another many years.