Every year a method of checking on the address of voters is employed.  When I began as Registrar 11 years ago, we utilized a paid, 3rd party firm to do an expensive mailing each year.  After collecting several years of data using other methods, we have now reduced the need to conduct a full "canvass by mail" to only once every four years.  The total savings due to this adjustment has been more than $50,000 in savings to the citizens of Greenwich.

Link to the Greenwich Time article