If you move, don't file your change of address notice with the Post Office. Directly notify the people who need to know. Then run your life on cash as much as possible.

The USPS rents change of address notices to over 22 different database companies who in turn rent the data to any number of direct marketers, investigators, and anyone else willing to pay for the information. Send change of address notices directly only to those people and companies that you want to keep posted of your whereabouts.