Hello,

EEPROM whether it is inside the MCU or outside it - the number of write cycles is fairly limited.

As has already been suggested, the best way is to keep writing into the save location as and when the data has changed and not wait for power down. Please remember that not all power downs are planned and in control.

And if you ask me for one such save location, it will be I2C RAM with a battery back up. And these chips draw in the order of microamps in the power down mode from the battery and as such battery life is not an issue.

Raghu