Who collects used postage stamps?

Collectors of used postage stamps are called philatelists. They seek out both used and unused stamps of historical or other significance. While collectors value some stamps at only a few cents, others have sold for hundreds of thousands of dollars.

When collecting used stamps, philatelists look for errors in the stamp printing process, such as incorrect dyes, off-center printing and text errors. Used stamps that contain a historically significant postage mark may carry additional value. The value of a used stamp varies depending on its condition, with stamps removed from envelopes without tearing or thinning worth more than those missing most of their gum from their back.