Three mugs can all be quoted at "3 mm" and behave like three different products. This piece breaks down what wall thickness actually controls: where the measurement is taken, how jiggering, slip casting and isostatic pressing each set a different floor, and why a thin wall is a hand-feel decision with a breakage bill attached. It covers rim thickness against lip feel and chip risk, handle attachment as the real failure point, and the weight-to-carton-to-freight math buyers usually discover after the container is booked. Written for buyers, brand owners and importers who need to write a wall thickness line with a measuring point and a tolerance instead of accepting an adjective. Ends with five specification lines to add before comparing quotations.