Toward the end of the roof’s life, the existing roof materials are salvagable most of the time, especially with metal roofs.  The labor and money wasted in removing and throwing away perfectly good materials is substantial.   Also, the cost for new  replacement materials is at its highest, $3.50-$7.00 / Sq. Ft.

On the other hand, cheap paint systems do not work at all, adding minimal durability, waterproofing, and rustproofing benefits.  Customers apply a substantial coating system a year or two later, frustrated that they were lured in by the attractive price $.40-$75 / sq. ft.  Watch out for fly-by-night painting operations.