Found an unopened jar of cinnamon in my cupboard with a sell by date of 2006. Would you still use it. As it is still sealed I wondered, but maybe it will have lost flavour?
I joke
I personally wouldn't use it on food but I would use it in natural decoration over the Christmas, I'd dry citrus fruit with the cinnamon, leave on rads and let the natural scent ooze around the house and give that real lovely Christamssy smell when you have visitors
Powdered or sticks ? powdered will have lost more flavour than sticks. But if I were you, I'd just add a bit more - such as 50 percent more than specified.