The point of a reorder point
A reorder point turns "we are running low" into a number. When stock falls to it, you order, and the arithmetic is simple: how much you sell in a day, multiplied by how many days you wait for the supplier, plus a buffer.
Most stockouts in small Kenyan retail are not caused by bad forecasting. They are caused by nobody having agreed the trigger in advance, so the order goes in when someone notices an empty shelf.