Should ductwork be replaced after 20 years?

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Tags

1. #system
2. #option
3. #probably
4. #deteriorate
5. #begins
6. #years
7. #however
8. #maximum
9. #should
10. #prudent
11. #replace
12. #ductwork
13. #reducing
14. #significantly
15. #replacement
16. #lifespan
17. #efficiency