@vanden maybe 15-20 years. I did find some packets that had had an invasion of a kind of moths - even though they were in a tightly closed box and some even still in the cellophane wrapping - must have already been eggs inside the package! So I threw those out. But most stays good enough if kept in a tightly closed container, preferably in the dark. It may lose a little 'strength', but very little. My problem is I want to replace one (largish) box, and I got a load of extra #tea from my dad. Bought metal boxes yesterday (now I have three) and some tea comes in their own metal boxes; I al;so have cardboard boxes but that will only be good for new cellophane-wrapped boxes. Still not enough!