The Trademark LawTrove provides some Frequently Asked Questions and answers about the United States laws of trademarks and their registration. These FAQs are not intended as legal advice: The trademark laws change frequently as new cases are decided and statues are enacted. Consult your own attorney regarding any question you may have that is specific to your situation:
It's unlikely, though not impossible that your registration will be maintained for an indefinite period. A trademark will last only as long as it remains in use to market and sell goods or services. You must prove and re-prove this use to the U.S Patent & Trademark Office (and to trademark offices in other jurisdictions) periodically in order not to lose your registration.
The U.S Patent & Trademark Office requires periodic affirmations that your mark remains in use in order to continue any registration. For example, you must file an affidavit of continued use during the fifth and tenth years of any registration, and at ten-year intervals thereafter. Ask your trademark attorney to maintain a docket sheet for these and other filing deadlines for your registered marks and to remind you of them in order not to miss key deadlines
Call your trademark attorney to discuss with him the possibility of sending a demand letter that the other person stop using your mark. The attorney should first ask you for information regarding the conflicting user, and perform an investigation in order to determine whether or not your trademark rights are both conflicting, and senior to the conflicting use. Then if both factors are present, a letter should go out to put the conflicting on notice of the conflict.
Notice will serve several purposes: (1) if the user acknowledges that there is a conflict and that your rights are indeed senior, he ought to stop using the mark voluntarily, and give you assurances that he has done so or (2) if he continues to use your mark in the face of the conflict, having given the opposing user clear notice your rights, you may be in a position to collect multiple damages and attorneys' fees if the matter goes to trial down to road.
In the face of continued defiance on the part of a conflicting user, schedule a meeting to discuss with your attorney all options to proceed to stop the use, and to obtain a estimate up front of the likely costs of the various procedures that may be available.