You manually track orders and may use a program such as Excel. It is difficult to deal with the issue of items being out of stock. You need to wait until the stock is replenished and manually enter the order at that time.
You need to manually track inventory costs through a manual process. You cannot track costs of inventory in and out of the warehouse at different costs and cannot change cost methods.
You have to wait until the order is filled and then manually update inventory. That gives an inaccurate picture of inventory levels.
You have to manually provide updates/transactions to inventory items when items are purchased, received or returned. That gives an inaccurate picture of inventory levels.
You manually track orders and lack an efficient method of processing back orders. You need to wait until the stock is replenished and then manually enter the order at that time. It is difficult to keep track of which customers still need orders filled.
Too much of your inventory is inaccurate and it is difficult to determine what to purchase. You do not do a physical cycle count often enough, and the delta between actual inventory is too high of a percentage. The system says you have something that you don’t too often.