How long they last depends on a number of factors, especially the type of roof. Generally, shingle roofs will last 15 - 20 years, depending on the grade of shingle. That being said, many insurance companies will charge you more once the roof is more than 15 years of age.
Depending on when specifically the roof was replaced in 2002, you may want to have a Wind Mitigation inspection done on the roof as it could potentially result in some discounts on your insurance rate.
Ask your FL insurance agent for additional information.