Common law trademark rights will continue for as long as the trademark is used in commerce and the owner adequately polices the mark. There is no expiration period for common law trademark rights but trademark registration will only remain valid if the owner files the proper renewal documents.

The owner must defend the trademark from infringers to maintain the trademark’s status as a source indicator. If too many people enter the marketplace with the same trademark, the mark will no longer identify a single source and the loss in distinctiveness will erode any trademark protection the mark once enjoyed.