HMC policy #510, Storage of Food and Non-Food Supplies, page 276 states "...canned and dry food without expiration dates are generally used within 6 months of delivery. These foods may be dated on the can or box to easily determine best storage period". This policy is referring to non-perishable foods, not to storage of spices.
Policy # 522, Food Preparation-Guidelines for Seasoning Food, page 296 states "Purchase seasonings in small quantities. Store in tightly sealed containers in a cool, dry location away from direct light. If properly stored, ground and whole spices have a 3-4 year shelf life".
McCormick's spice manufacturer recommends the life of spice to be 2-3 years for ground spices, 3-4 years for whole spices, 1-2 years for seasoning blends, 1-3 years for herbs, and 4 years for extracts except pure vanilla which lasts indefinitely. Whole peppercorns, nutmegs, and cinnamon sticks hold onto their flavor for years and potent whole spices like cloves, cumin and cardamom also last a very long time.
Spice shelf life is dependent upon proper storage with tightly capped containers stored away from heat, moisture and direct sunlight. It is important to replace lids tightly after each use, and not to store spices and herbs over the stove, steam table, dishwasher, sink, or near a window. Spices and herbs should not be stored in the refrigerator with one exception: members of the red pepper family including paprika and chili powder will retain color and freshness longer if refrigerated as long as they are protected from condensation and caking.
Test the potency of the spices if you question their flavor ability by crumbling dried herbs in your hand; if the color and aroma are evident, it will still do its job. For ground spices, shake the jar, let it settle, and then give it a sniff. If there is no smell, then it will not be flavorful and should be discarded. To get the most flavor from herbs and spices, make sure you don't shake them out of the bottle directly into something you're cooking since it will contact steam and harm the shelf life. Instead, measure into bowls or measuring spoons before adding to the food.