Here's an interesting bit of information from McCormick's Facebook page.
Apparently, with the exception of black pepper, McCormick stopped packaging its spices in tins more than 25 years ago. And it is true that spices lose flavor and aroma over time; fresher is better.
One more tip, this time from What's Cooking America. The site says that McCormick spices in bottles printed with, "Baltimore, Maryland," on the label are at least 15 years old. So if you have any of those, you might want to think about tossing them.
If throwing away containers of spices seems wasteful, look at it this way: you were already wasting space if you've had spices for so long without using them. And you can repurpose those tins as planters for little succulents.
More on tins as planters at Apartment Therapy.