EEPROMs have a limited life (i.e., cycles they can be written to and erased). For the device you mention, it is 100,000 erase/write cycles, after which failure is more likely. The actual life of the whole device may be longer. Depending on the quantity of data written, this can be accomplished by remapping data to other sectors on the EEPROM that have not been subjected to the 100K erase/write cycle limit.