Customers orders 30 Beanies to be embroidered. I order 36 just in case he orders a few more. Today comes a message from him.
He now needs 37 Beanies by this Friday. My next order with the supplier will be at the beginning of next week. Do I order the extra one or wait until next week?
Of course I wait until next week, the transport cost is three times more than the beanie.
Damn annoying that you can never outguess the customer.