A shipper should ALWAYS double box. The outer box should be 6" bigger in all dimensions, to allow 3" of packing between the inner and outer box. Lack of double boxing results in one in 10 shipments arriving damaged. An extra 3" of peanuts should reduce the risk of damage to 1 in 100 shipments.
Original factory packing is not sufficient, especially if it is a few years old or the item has been shipped a couple of times. It is only sufficient for the initial shipment, and even then when it is banded with multiple boxes on a skid. Another benefit of double boxing is it preserves the strength and appearance of the original box.
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