Currently The Department of Veteran Affairs (VA), insists on sending important mail to outdated addresses. The reason for this, in their own words (https://iris.custhelp.com/app/answers/detail/a_id/3045):
"It is important to note, different departments within the VA do not use the same computer system. Therefore, if you have health benefits, education benefits, etc., each individual department will need to be contacted to correct your address."
This would be easily and cheaply solved by having them share this basic piece of data (which could also be applied to other government agencies, such as the Post Office). All it takes is having each database reference the same common piece of information, thereby improving care for our soldiers, maybe even preventing a few suicides.