Demurrage and detention

Each charge comes with a period of free time, negotiated in the carrier contract, after which a daily rate applies, often on a rising scale. The clock does not care why the container has not moved. Customs holds, missing documents, a full warehouse and a labor shortage all produce the same invoice.

The most expensive version is the one where both run in sequence: demurrage while the box waits in the terminal, then detention while it waits at the warehouse.

A large lot arriving over many containers needs intake capacity to match its arrival rate. If the warehouse cannot unload at the rate the containers land, the surplus becomes detention, and the cost lands on the party that controls the delivery schedule. That is a practical reason to stage deliveries rather than accept a schedule set by the seller, as in warehouse throughput.

Negotiate free time up front rather than disputing charges later, since free time is a contract term and demurrage invoices rarely move. Pre-clear customs where possible. Match arrival rate to intake rate. And track which containers are approaching the end of free time daily, because these charges are almost entirely avoidable and almost never avoided.