This depends on the use of the container. However, shipping containers are designed and manufactured to cope with a long and arduous life moving goods around the world. As such, they are very sturdy and secure. A used container will usually have been in international operation for in excess of 10 years and sometimes longer but depending on your use, depending on its location and reasonable maintenance it is not unreasonable to expect a further 10 plus years of use. New containers will have completed one journey from their country of manufacture and with reasonable use and maintenance can be expected to complete over 30 years as a storage container.