"Myth: Tea doesn't have an expiration date. If you've got bag of tea sitting around for years, it's time to toss them. The shelf life of tea is about 6 months. Over time, the powerful flavonoids found in tea are reduced. To get the most out of your tea, store it in a cool, dark place."

Source: https://www.foodnetwork.com/healthyeats/healthy-tips/