The important influence of surface treatment on paint durability has been highlighted by Francis (see reference below) with durability data for a certain paint system in a certain environment. It was noted that the different surface cleaning/preparation methods were applied professionally.

Click on image to enlarge
Durability data from R. Francis: "Beating Rust on Farm Buildings",
published on web site of Australian Corrosion Association Inc.

References/Literature:

R. Francis: "Beating Rust on Farm Buildings", published on web site of Australian Corrosion Association Inc.

Links: