somewhere else they were discussing how to use a 555 to time 55 years, and how for such a long period you'd need impractical resistance and capacitance values. easy workaround would be to set a more reasonable period, say, 1 sec, and use a counter to know when you hit 55 years. coincidentally, 55 years is 2 ** 30.7 seconds, so it'd just fit in a 32 bit register.

though i take you were thinking about counting clock cycles or something in which case surely your register would overflow

That 10c microcontroller has 15 32 bit registers, allowing you to make up to a 480 bit counter. That ought to be enough until long after the heat death of the universe.

It also has 2k (16384 bits) of SRAM, allowing even larger counters.

It runs off 2.8V - 5.5V DC, so supplying power is pretty trivial. Doesn't need a crystal, though of course adding one will improve the timing accuracy.

You don't check the eeprom value by flowing current thru the cell as you do with cap