Copyrights and Patents have a set period of time before the expire. Trademarks last for as long as they are in use. There is a schedule, and requisite fees, for maintaining registration of the trademark.

The USPTO only registers a mark. You, as the owner, are solely responsible for enforcement.

The official registration will serve as a stronger legal claim to rights over the name/design than an unregistered mark, but infringement claims will need to be pursued by users through civil courts.

A trademark watch service is a company that monitors new trademark applications. They receive data on all trademark filings in nearly every industrialized country. If they find a filing that matches your trademark, you will receive an email with the details. This service means you don’t have to monitor the databases yourself to catch potential infringement.

After a registration certificate has been received, regular registration maintenance documents and fees must be sent. Within 6 months of the end of the first 6 years period, a Declaration of Use or Excusable Nonuse under Section 8 must be filed, along with applicable fees. Within one year before the end of every 10 year period after the registration date, either a Combined Declaration of Use, or a Excusable Nonuse/Application for Renewal  under Sections 8 and 9, must be filed along with applicable fees.

A Section 8 Declaration is a formal statement to the USPTO affirming that your registered mark has been in use continually for five years. Failure to file the declaration on time results in loss of registration and cancellation of federal trademark rights.

This doesn’t mean your trademark has been cancelled. The benefits of federal registration are lost.

A mark may be considered immune from challenge, or rather- very difficult to challenge, if it can demonstrate there are no legal decisions against the mark, no challenges pending, a section 15 declaration, and the mark is not and has not become generic. It is basically incontestable on the common ground of lacking distinctiveness. At the 6 months prior to 6 years of registration point, a Section 15 Declaration, a Declaration of Incontestability, may be filed with the USPTO. This declaration isn’t necessary for maintaining registration, and no loss of rights occurs without it. Its purpose is to expand rights by making it more difficult to challenge the mark.

This is the form needed to file at the 10 year period, or within a year leading up to the 10th year after registration began. The declaration includes a verified statement of the trademark being in use in commerce, along with evidence showing that use. This is filed in combination with a Section 8 Declaration.

Yes. This is called assignment. A few common reasons why a name might need to be changed on the trademark might be selling the business the mark represents, or a name change (perhaps after getting married). The USPTO has a short video on Assignments and Ownership Changes.