Why not use either Sterling Silver or Fine Silver exclusively?
It really depends on the look and functionality I am seeking to achieve. Without work-hardening (usually by hammering or tumbling), Fine Silver would be too soft to use in most jewelry. I use Sterling Silver solely in my Sonoma Collection for its strength and smooth shiny look it gives to chainmail. The textured hammered look of the SoMa Collection lends itself solely to the malleable properties of softer Fine Silver.