Three things set frequency: the shelf life a product group has left when it reaches the store, the store's cold storage volume and its rate of sale. A store with a small back room and fast sales cannot live on two trips a week; a store with a large back room and slow sales wastes four. Even within one chain, stores need different frequencies.
| Limit (example figures) | Calculation | Trip interval |
|---|---|---|
| Storage: room for 100 units, 40 sell a day | 100 ÷ 40 = 2.5 days | 2 days at most |
| Shelf life: 5 days left on arrival | interval must be shorter | under 5 days |
The smaller limit applies: a delivery every two days, or 3-4 trips a week. Dry, long-life goods do not have to travel on the same schedule as short-life chilled goods; dry can go once a week and chilled three times. Where the chilled trip can be run with a small vehicle this adds no vehicles, and with a large vehicle it lowers the load factor. Move the delivery hour away from the store's busiest time as well, so the interval from receipt to shelf shortens.
Before changing the whole network, run four weeks in two similar stores. Have the same three numbers on record beforehand: value of waste, count of empty shelves and cost per trip. Frequent delivery shrinks store stock, which frees back-room space and cuts handling and spoilage, but that gain does not show up in the transport report, so bring waste into the same table.
