http://www.greatdata.com/zip-code-questions.htm http://www.greatdata.com/zip-code-questions.htm Q: How often do the ZIP / postal codes really change? A: U.S.

http://www.greatdata.com/zip-code-questions.htm http://www.greatdata.com/zip-code-questions.htm Q: How often do the ZIP / postal codes really change? A: U.S. ZIP Codes change sporadically. Most of the time there's just a few changes, but every now and then (especially around July 1st) there will be major changes. ---- ... In other words, they change all the bloody time.