Unlike patents and copyrights, trademarks do not expire after a set period of time. Trademarks will persist so long as the owner continues to use the trademark. Once the United States Patent and Trademark Office (USPTO), grants a registered trademark, the owner must continue to use the trademark in ordinary commerce.Just using the mark, however, is not enough. Trademark section 8 requires the owner to provide evidence that the trademark continues to be in use. To show the mark is still in use, the owner must file a section 8 declaration.That proof takes the form of a sworn statement from the owner that the mark is still in use. The owner must file the declaration after the fifth anniversary of the USPTO's registration of the trademark but before the sixth anniversary. For a fee, the owner can request a six-month grace period if the declaration is not filed prior to the sixth anniversary.