Since I am a moderate smoker, a bowl or two a day, some days or stretches with none for lack of time or opportunity, I am equally concerned about not keeping blends too long. This applies mostly to aromatics, but also to some constituent Latakia and other leaf that can, at least in some instances, fade, or fade quickly once a tin or jar is opened. I should mention, I am enough afflicted with TAD so that I tend to accumulate more blends than I am smoking at the moment, by far. I rely on the concept that most blends only improve, but often, some do and some don't.