Most laypersons have a preconceived notion of "manual labor" that heavily features "sweat equity"—work performed by janitors, mechanics, farmers, plumbers, etc. But what about retail store employees? They don't make the products. They don't typically exert a comparable amount of physical effort compared to a commercial janitor or an assembly-line worker. But a retail employee is on his or her feet the whole shift—stocking or organizing shelves, doing minor cleaning, and perhaps checking a stockroom to address a customer service need.