Between the fifth and sixth year after federally registering your mark, you should complete and file two important forms with the PTO: the Section 8 Declaration and the Section 15 Declaration.
To file the Section 8 and Section 15 Declarations, you must still be using your mark in the manner described in your registration certificate. This means that you must still be using it, at a minimum, on the same products or services and in the same way (on packaging or pamphlets, and so on) as you originally stated and be able to come up with samples that demonstrate your continued use.
If your mark was registered on or after November 16, 1989, it must be renewed within ten years from the date of registration. If your mark was registered before November 16, 1989, it must be renewed 20 years from date of registration. In addition to filing a renewal application (Section 9), you also must file another Section 8 Declaration at the same time.