The data in EEPROM will only be amended until all the components are operating satisfactory, this will likely be soon after startup but I am grateful for the warning of write limits. How many times? I'm not expecting thousands but I'll have to remember the Nano I use for bread-boarding could be limited if I use it in a circuit afterwards.
In the circumstance where a write fails due to this limit, does it affect the entire EEPROM or just that memory address?