Last mile

The last mile is the final leg of a shipment: from the last distribution point to the recipient's address or pickup location.

Why it is the most expensive leg

Because it loses all the economies of scale of the rest of the chain. A trailer moves thirty tons in one trip with one driver; the last mile moves one parcel per stop, with a driver who also has to park, knock, and sometimes find nobody home.

Add factors that do not exist upstream: urban traffic, delivery windows, incomplete addresses, and failed deliveries, which double the cost of that shipment because it has to be reattempted.

What the warehouse actually controls

The last mile is executed by the carrier, but the warehouse influences three things that make it cheaper or more expensive:

1. Order accuracy — a wrong shipment generates a return and a reshipment: three last-mile legs instead of one
2. Packaging quality — in-transit damage produces the same effect
3. Handover time to the carrier — leaving within the pickup window decides whether the order travels today or tomorrow

That third point is what makes the distance between warehouse and dispatch point — the airport or the carrier's hub — matter so much in an e-commerce operation.