Maintaining a database of postal mail addresses requires them to be maintained over time and validated. Conventional wisdom is usually that an address database should be largely static and never change after data entry unless someone physically moves. However, as in many cases, conventional wisdom is not correct in this case. Both the United States Geological Survey (USGS) and the United States Postal Service (USPS) recommend that physical street addresses be maintained at least once a quarter via a process named geocoding, which includes street name, city, state and zip code validation.