The operating enviroment and conditions, flying techniques have not changed.
Only the blades have changed. Obviously the old blades 40 thou skins were rigid enough to hold their shape even if not bonded correctly. The new blades have an 8 thou skin. Robinson's rushed production run to manufacture dash 4 blades probably came at a quality control sacrifice. Operators in erosive enviroments are going to have keep their blades painted (all eviroments), perhaps an outboard end repaint every 300 hours.
bigruss