Is is worthwhile checking my old heating ducts for degradation?

Is is worthwhile checking my old heating ducts for degradation?

This report from Sustainability Victoria shows that ductwork is responsible for a significant amount of losses.  "Retrofitting old gas heating ductwork in pre-2000 houses could achieve average annual energy bill savings of around $235 per year and average annual greenhouse savings of 745kg per year".  For more data, visit their report here: https://assets.sustainability.vic.gov.au/susvic/Report-Energy-Gas-Heating-Ductwork-Retrofit-Trial-Sep-2016-1.pdf