Jerry,
You have a good case re D-76, since it's pretty similar to Xtol, which I make last > 24 months by mixing in 10 500ml sealed bottles and it's not worth doing the work to make D-76 last >24 months.
But generally, and I'm sorry, I didn't explain what I meant very well,it is an advantage to have long lasting developers as many can be made up to choose from ,eg, alongside this solvent developer Xtol occasional amounts of other developers can be used provided they last >24 months.
So one can have a choice of Xtol, Rodinal,PMK Pyro and anything else can be made to last, I have used quite a few.Having a collection of long lasting developers is not strictly necessary but it makes film developing more interesting IMO.Anchell and Troop wrote a book about it.