An apparatus and a method which use a programmable reliability aging timer are provided. The apparatus includes a performance circuit configured to perform a function of an integrated circuit (IC), a memory unit configured to store a lifetime of the IC, a controller configured to set an aging target condition according to the lifetime stored in the memory unit, and a reliability aging timer (RAT) configured to apply stress to a test pattern according to the aging target condition and sense a result of the stress to determine the degradation of the IC. The RAT refreshes an operation of the performance circuit if it is determined that the IC degraded before the lifetime of the IC.