How long does a Trademark registration last?

For a trademark registration to remain valid, an Declaration of Continued Use (Section 8) must be filed:
(1) between the fifth and sixth year following registration,
(2) within the year before the end of every ten-year period after the date of registration.
The registrant may file the Section 8 Continuation Of Use within a grace period of six months after the end of the sixth or every tenth year, with payment of an additional fee. The registrant must also file a Section 9 Renewal application (Section 9 Renewal) within the year before the end of each successive 10-year period following the date of registration, or within a grace period of six months thereafter, with payment of an additional fee. Assuming the Section 8 Continuation Of Use and Section 9 Renewal are timely-filed as indicated above, the registration will be renewed for a 10-year term. If the Section 8 Continuation Of Use and Section 9 Renewal are not timely filed, the registration will be cancelled. Registrations cancelled due to the failure to file a Section 8 Affidavit and Section 9 Renewal cannot be revived or reinstated.