Fixed bin is a storage method whereby products with the same part number are stored at the same (permanent) location in the warehouse. When is that particularly useful?

Especially in case of products that need to be stored in large quantities, or need to be kept together because of specific requirements. In most cases, the free bin (or: open storage) system is a better solution. It is the most efficient way of storing and usually results in lower storage costs. Moreover, the free bin location system ensures that goods do not need to be moved when a position is full (which in turn entails additional risks).