The size of inventory kept by manufacturers differs based on the surrounding economy and geography.

In some countries, the manufacturers cannot trust those handling the transport of the needed materials. A lack of trust occurs when the transporters need not concern themselves with their reputation, competition, or profits, as in government-run enterprises. A TV manufacturer might choose to handle its transport, but this is almost always inefficient because it is simply not an area of specialisation.

Sizeable inventories insure against disruption but are costly and earn nothing. The countries that can rely on efficient transport of materials save money by warehousing only the necessary resources.

Geography also plays a role in the size of inventory. The quality of roads and navigability of waters directly affects the feasibility of frequent deliveries.

Ultimately, inventory is a substitute for knowledge - a company with perfect foresight would know how much material is needed until the next delivery and order only that much. A lack of information about the economy’s future also plays a role - if it is in a downturn, it helps to have inventory to sell while manufacturing is on hold.