Can spices expire?

I recently heard that expired spices can be very bad for you. Since I have had spices in my cupboard since I moved into my first apartment 6 years ago I decided to explore this topic for myself. And as I think about it, there is nothing I would keep in my fridge for six years and then eat it, so why spices?  This made me want to investigate.  Over the past few weeks I have been reading through web sites and blogs about expired spices and what I have concluded is this: expired spices may not be bad for you but they probably are not good for your recipe either. Expired spices lose their flavor, color, and smell which is how you will know if they are not good any longer. 

I discovered the McCormick's Spice Dating Calculator


According to McCormick's website, ground spices are to last 2-3 years. If you open them and their color appears to have faded, more than likely their aroma and flavor has faded also. Toss & replace.  You can look on the bottom of the bottle for an expiration date or sometimes they include a code. If you type the code into the McCormick's Spice Dating Calculator it will tell you if its still good.  5 of the 5 McCormick spices I inspected in my cupboard all had "Best By" dates and the soonest is in 2012 so I guess I don't have much to worry about (or replace) for a while.  I don't think these are the ones I purchased 6 years ago, those must be at the back of the cupboard somewhere.