The smaller Part B Developer component doesn't last very well at all once opened. A few months, yes, but not as long as the other Dev and Blix concentrates. If it's gone brown and oxidized, too late.
MY method, for sake of optimal consistency: I mix fresh, only enough for a single day's work session at most. I never replenish anything, always one shot usage in drums. (If you have an automated processor intended for monitored replenishment, that's a different story.) When in doubt about the storage life of concentrates, I buy fresh chemistry to have on hand in case the older stock proves unreliable.
Any serious storage of mixed chemicals of any kind - amber glass bottles, period. Thin recycled poly or (egads) non-poly camera store style darkroom jugs are permeable to oxygen and quite inferior. Any serious Scientific or lab supply house like LSS will offer a significant range of storage options along with true specifications abut chemical compatibility etc. But if you don't mind the risk of breakage, true glass bottles with matching caps if the best option, especially on a limited budget. I don't know about recycled Soda containers; but since carbonation is basically dilute carbonic acid, there's some merit to that.