 Since the number of writes to EEPROM is limited Atmel specifies 100,000 write cycles in their datasheets a well designed EEPROM write routine should compare the contents of an EEPROM address with desired contents and only perform an actual write if the contents need to be changed.Note that erase and write can be performed separately in many cases, byte-by-byte, which may also help prolong life when bits only need to be set to all 1s (erase) or selectively cleared to 0s (write).Atmel's AVRs have a two-stage, single-level pipeline design.