For the love of tea! Stop saving that special tea you purchased on that one trip to (enter exotic place here). So many times I will be chatting up the love of tea with someone when they declare they have a tea they purchased that was either really good or really expensive. It was so special they decide to lock it up and keep it for a "special occasion". When I inquire about how long ago they purchased the tea they usually have a good decade to count. WHAT???
Tea is meant to be used immediately. You should be consuming all of that special tea as soon as you possibly can to experience the quality while it is still intact. 3 things degrade the integrity of the flavor. Light, air, and heat. Once you open your tea and expose it to the elements it starts it's decent into becoming stale. Unless you suck all of the air and stash it in a cool dark place. But even with doing so it will only "stay fresh" for about 2 years before it loses it's special quality. You may still drink it if you like a flat tasting version of that wonderful experience. It's like taking out old photos and seeing how the colors have faded. So will the flavor.
Please, drink your tea.