SouthernAtHeart:
Thanks. I know I've read something about only writing some many times to the EEPROM, and there's no moving parts in there is there? I'm sure there's a big difference so how.
Well yes, it was a glib statement - most electronic devices only have electrons moving.
An EEPROM involves programming with high voltage gradients to force (well, quantum-tunnel) electrons through an oxide insulator -
this stresses the insulating layer and leaves electrons trapped in flaws in the oxide, these build up and eventually cause
mis-behaviour of memory cells - so technically the electrons don't wear out but the flaws in the insulator allow degradation
of the device in this manner.
Electronic devices also age (the material isn't stable long-term), suffer from thermal cycling (causes mechanical stresses),
and various effects, but in general should stay reliable if kept below "absolute maximum ratings".