My tea bags are expired, can I still use them?
Tea bags will be fine for at least a year in the pantry, but even long after that, they're still safe to consume.  They just might change colour or flavour.

If your tea has an expiration date then it's just for best quality, not safety.  I've personally found tea bags sitting at the back of the pantry that were more than 3 years old, the packaging had even started to fade, and the tea was still fine.  I just had to steep it for a little longer.