Before using replenishment recommendations product lead times and days of stock should be configured.
The lead time is the amount of time that elapses between placing a purchase order and receiving products.
Days of stock is a period of time for which you’d like to have enough stock, or, in other words, the stock cover.
For this example Inventory Planner recommends you to purchase 36 units of the Mango dress that will arrive in 14 days if you place your purchase order today and will cover the following 30 days.
The lead time usually depends on suppliers and it's easy to estimate. To see average lead times go to Reports > Good Received Note.
When in doubt add additional days in the lead time period.
Scenario 1 (recommended) - the lead time is less than days of stock
Days of stock can be seen as the frequency of purchasing. If you purchased your stock for 90 days you should place your next purchase order for this supplier in 90 days assuming that projected sales are correct.
When lead time is less than the cover you don't have to take immediate actions once your stock is arrived. For example if you received products for the following 90 days and the lead time is 30 days you have 60 days to do something else.
Scenario 2 - the lead time is equal to days of stock
In this case right after receiving products from a supplier you should review your stock place another purchase order.
Scenario 3 - the lead time is more than days of stock
It makes sense to use when your lead time is very long (longer than 90 days) and you don't want to keep that much stock. In this case you will always have multiple pending deliveries from each supplier.