Buy Only What We Need, When We Need It
In purchasing goods and materials, we should not buy more than we need just because it appears more cost-effective to do so.
Buying extra leads to wasted money. Even if a quantity purchase would temporarily lower the unit cost, we risk the need for warehousing, carrying interest on inventory, or having obsolete items as specifications change. We may even end up with totally useless inventory.
A manufacturer should devote itself to creating profit from manufacturing. It is important to consider buying only what we need, when we need it.