Actually diet drinks gave up us. They just "fizzled" out.
Over the last year we noticed that we were letting our stash of diet drinks (cola, lemon-lime,dr. pep) go past their "sell by" date. Have you ever tasted that? YuckYuckandmoreYuck. I think we even tried to poison a few friends and relatives who came here for a party. We never even dreamed that we were drinking (and serving!) expired drinks.
Don't those bottled drinks last forever? NO, of course not! So after trying to check the "sell by" date--good luck with that-- on plastic bottles, we just let our stash go and started drinking San Pellegrino water. I have to admit that the first bottled water we ordered from Amazon was "expiring" and had lost its fizz factor. We drank that up quickly. Ice cold, and you do not really notice. Not so with our old diet standbys.
So we gave up diet drinks here at home. That doesn't mean that we won't still need to pay attention to "sell by" dates on our water, but at least we won't poison anyone!