Since tea is very dry, one would think the product quality wouldn't change much, but in reality it's very easily degradable.
This article will show some ways to store tea and keep the taste from fading.
If you have to store tea for a long time, you can use your refrigerator or freezer, but only if it's unopened. After taking it out of the fridge, leave it as it is and when it reaches room temperature, open it. If you open it right after taking it out, the difference in temperature will make the tea leaves will absorb the moisture and will have adverse effects on the color and smell.
Store opened tea in a cool, dark place, but do not use the refrigerator. A cool place that gets no sunlight and stays at room temperature is ideal. In the refrigerator, tea can absorb the smell of food and this can have an effect on the smell of the tea. Also, when taking it out of the fridge, it will be exposed to the outer air and the difference in temperature can cause mist to form, which will dampen the tea and ruin the quality.