We never think milk or butter or eggs will last forever, but for some reason we look at a tin of allspice like it’s the portrait of Dorian Gray, and will never age. So here’s how to gauge the life of your dried spices.Give the old ones a whiff. If they don’t mesmerize your senses, out with them! Also, keep them away from the heat because it destroys the volatile oils that give spices their distinctive flavor. Don’t store them in sunlight either. Find a dark, low-humidity cabinet.Because spices are getting really expensive (let’s not even talk about saffron threads), don’t buy any more of one than you can use in six to nine months, even if you’re shopping at Costco.And finally, if you really want your pies to sing, get a spice grinder and use whole spices. Like the eminent Mister Gray, they can keep going for years.