I think the general wisdom is that keeping your unopened, sealed bags
of tea in a refrigerator is the best way to store them. However,
there are a couple things to be aware of.

Make sure you let your tea return to room temp. before opening the bag
for the first time, otherwise atmospheric water vapor may condense on
the leaves, which can cause problems with storage.

Also, don't return an open bag to the refrigerator, unless you are
*certain* it is airtight (which is difficult unless you have equipment
designed specifically for the task). You will likely pick up odors
and moisture if you put an open bag back into the fridge.

I imagine storing tea in a freezer is even riskier than storing it in
a refrigerator, and you have the added danger of freezer burn.

-Brent