The thing you folks using outdated carts are missing, is the reason for the dating!!
Pigmented inks have a tendency to settle. The name brands of inks are better at reducing this tendency, than third party inks. But regardless, it is quite hard to keep pigments in suspension indefinitely. At the same time the pigments settle, they can also clump, which can lead to damper clogs, which lead to nozzle clogs. You can help the settling situation by occasionally taking the carts out and shaking them, but this won't alleviate the possibility of clumping.
If you keep the same set of carts in your printers more than a year, you can be asking for troubles, if not with print consistency, then with "clogs from hell".
You should buy sizes you might use up within a year or so. Never buy large capacity carts of colors that get used very little. I know that 3880's don't have multiple cart sizes, but this information is for folk using other machines.
And the number one thing to remember about inkjet printers, "they like to be used"! Especially Epsons. If you are a "light" printer, you should plan on doing a weekly "throw away" printing, just to keep the print heads in shape.