Containers are intended to be used constantly, being loaded with new cargo for a new destination soon after emptied of previous cargo. This is not always possible, and in some cases, the cost of transporting an empty container to a place where it can be used is considered to be higher than the worth of the used container. Shipping lines and container leasing companies have become expert at repositioning empty containers from areas of low or no demand, such as the US West Coast, to areas of high demand, such as China. Repositioning within the port hinterland has also been the focus of recent logistics optimization work. Damaged or retired containers may be recycled in the form of shipping container architecture, or the steel content salvaged. In the summer of 2010, a worldwide shortage of containers developed as shipping increased after the recession, while new container production had largely ceased.
