You guys are talking strictly about a filter that's in storage right, once it's installed it should last for as long as it is not used up? Or does it actually have a limited life time even after installation? I'm single, I presume one filter is going to last me a year, maybe even longer. Or do they go bad even with not a lot of usage?
I think the twin packs are for changing both at same time as they have different levels of filtration. Though that may be overkill for me, I can maybe look for a system that has just one filter. I mostly just want to get rid of chlorine taste, our water is not really that bad, it's just better once you filter it. Will probably also be better for making coffee.
If I do end up buying multi packs, would it be enough to simply store them in a sealed container? Given their shape it would be optimal to use an ABS pipe with a screw end, could just use that to store it, and that will make a pretty nice seal. Could throw in some of those "do not eat" packets for good measure.