Storing e-juice

Does anybody else have trouble with their e-juice losing flavor over time? I have about a dozen flavors of juice from about 4 or 5 different companies. None of them is older than a couple months, because I've only been vaping since January. And yet all but the newest ones have started to lose their flavor, becoming much less intense and in some cases tasting pretty much the same (any tobacco flavor ends up tasting like the same base).

Is there anything I can do to keep this from happening? I keep them stored in a cabinet in my kitchen but it's not right over the stove or anything, and they're all in their original bottles (some plastic, some glass).