Just a comment on this: my student house is still receiving mail from students who lived there about 5 years ago. We're also receiving credit card bills, tax returns, magazines from the last folks who lived there. I've never changed my address because I don't want other people getting my mail once I leave (especially sensitive stuff) and the changeover can take some time. Heck, we still get my sister's phone bill at my home even though she moved out a year ago and called them several times.
My parents just call me when I get important mail