Inventory, purchasing and demand forecasting for retail stores.
Demand forecasts that account for lead time, safety stock and the days a variant was unsellable — and that show their working, so a suggestion can be argued with.
Partial receipts, over- and under-deliveries, and landed costs allocated across freight and duty, written back to inventory as it arrives.
Blind stocktakes on a phone, transfers between locations, and a reason code on every adjustment so the variance can be explained later.