Had timing belt replaced in January 2012 now its.

Had timing belt replaced in January 2012 now its October 2012 they telling me my timing and drive belts are dry rotten. Had service at the Kia dealership would it be that the timing belt where dry rotten that they replaced in January from the originals. If they dry rotted since January should they not just replace timing belt. How soon should the drive belt be replaced from original