I've had a bottle for a year that doesn't seem to have (visibly) separated at all.
I always heard rumours that the stuff never went bad, and I just thought people meant relative to other developers... but 7-8 years? Wow!
I've heard stories about 30 year old Rodinal that was still good. In a time test, I don't know if HC-110 or Rodinal would win but both will really last longer than the time it takes to use them, even if you develop only a little bit a year. FWIW HC-110's expiration date says "indefinite" haha
~Stone | "...of course, that's just my opinion. I could be wrong."~Dennis Miller