Safety stock is the minimum level your inventory should ever reach in an ideal world. It is there to minimize the impact of supply and demand risks that arise. The higher the risk of the below, the higher the safety stock requirement will be:
Unreliable supply
Unpredictable demand
Short replenishment cycles
High target fill rates
Long lead times
The lead time, safety stock and replenishment cycle within the app are in days – this is essential in order to deal appropriately with future demand, which may be seasonal.
For example: 10 days of safety stock out of season might equate to 5 units while 10 days in peak season might equate to 300 units. Using days is key to computing dynamic optimal levels that react to changes in demand.
In order to decide WHEN to order and HOW MUCH to order, the “days” need to be converted to units so they can be tested against your available on hand stock.