When is a contractor grade extension cord worth the extra money?

A contractor grade cord is worth it for construction sites, continuous outdoor use, or any job where the cord might get yanked, rained on, or driven over. Consumer grade cords are fine for lamps, holiday lights, and occasional indoor power tool use. The main advantages are thicker wire gauge, tougher insulation, and molded plug ends that don’t crack. For heavy use like running a miter saw all day or a space heater on a long run, the extra cost for a 12 or 10 gauge contractor cord is peace of mind.