You'll need to look in the applicable edition of NFPA 72 for your local jurisdiction. Having said that the frequency for testing hasn't changed much over the years.
NFPA 72, 2007 edition, 10.4.1.2 "Reacceptance Testing" addresses testing after a modification has been made to the system. Section 10.4.4 "Testing Frequency" addresses regular testing. Table 10.4.4 give you the test frequency.
Regards,
Dan