(this article is a work in progress). My own advice will be added later...
Having a system that regularly writes parameters to the EEPROM can wear out the EEPROM, since it is only guaranteed to endure 100 k erase/write cycles. Writing the parameters to a circular buffer in EEPROM where each of the elements in the buffer can endure 100 k erase/write cycles can circumvent this. However, if the system is exposed to RESET conditions, such as power failures, the system needs to be able to identify the correct position in the circular buffer again. This document describes how to make safe high endurance parameter storage in EEPROM/
Read more: http://www.atmel.com/images/doc2526.pdf
Simon is IT professional with interests in web design, electronics, photography and astronomy. He writes about PHP, Yii, Joomla!, Arduino and several other topics.