This is a quote from a reed maker
Bernard Vandoren: "Cane, being a natural product, is likely to change when the weather and the hygrometrical conditions change. When just finished, a reed may have all of the required qualities, but this same reed, after a period of time, may no longer be acceptable due to external factors which might have modified it. A great American musician recently came to choose his reeds in Paris. When he returned home to the States, he did not find them to be the same as when he had tried them in Paris. The reeds had changed during his trip.
"Reeds are likely to be compared with wine. A wine, tasted at the harvest has certain qualities, which, during travel and time, will be altered. To be able to re-live those same sensations it is necessary to be in the same state you were in at the time of the tasting (sampling). A wine has to be tasted regularly, as it is sensitive to time and external factors. In the same way, an excellent reed will change with time and climate. And in order for the reed to reach its best, it has to be played regularly."