The life expectancy of a well-maintained new container is at least 25 years. Most last a lot longer. Grade B containers, therefore, will likely have at least 10 years in them, though Grade C containers will be a little less.
However, even the poorest-quality containers can often be brought back to life with a little effort. We know of some containers that have been in use for well over 40 years. Check out our used containers page for more details.