The FTC had intended for phone numbers listed on the national Do Not Call List to be renewed every five years or dropped from the list. Since the Federal Do Not Call Act, 15 USC 6101 note, was enacted in 2003, this would mean that phone numbers would start falling off the registry next year. Legislators have stepped up to make the registration permanent, though, and the FTC has promised that they will not drop any phone numbers from the Do Not Call Registry while bills are pending to make the registry permanent. Read the full text and check the status of the Senate Bill and House Bill. So no need to renew your registration. If your number is on the list, it will remain there. If not, register at the Do Not Call site.
More information on Do Not Call and other telemarketing issues is available at Mass. Law About Telemarketing.