"Reorder at 10 units" is the usual rule, and it is wrong for every product that does not sell at the same rate or arrive in the same time.
reorder point = (average daily sales × lead time in days) + safety stock
Something selling 0.8 units a day from a supplier who takes 22 days:
A flat threshold of 10 would have you ordering when there are 13 days of stock left against a 22-day wait — out of stock for over a week, every time, on your best seller.
The same product from two suppliers has two reorder points. Use each supplier's own history, and pay attention to the spread as well as the average: a supplier averaging 20 days but ranging 12 to 40 needs far more safety stock than one that is reliably 25.
Work it from real sales over a recent window rather than a number typed in once. A product that has doubled in popularity since you set its threshold is the one you will run out of.
In the app
Every figure on this page is something PepStock keeps without being asked — landed cost per batch, each purchase's own cost, what every reseller is holding, and the per-mg ranking at one kit and at ten.
