Derived directly from a bill of material structure (BOM) of an independent demand item. So, dependent demand is normally calculated from the quantity of the independent demand item, e.g. an order for 1 000 bicycles would result in a requirement for 1000 saddles. An inventory item may have both types of demand – dependent and independent – at any given time. For example, a part may be not only the component of an assembly, but also sold as a service part – the saddle of a bicycle