If you are like most people, your spice rack or cabinet probably contains dried herbs and spices that have long since lost their freshness. It can be a painful process to toss out almost full containers of costly spices, but the flavor of your culinary creations will really suffer if you do not. Look at your herbs and spices and notice if the color has faded, or if the aroma has diminished after crushing a little in your hand. These are signs that it is time to replace them.
The best way that I have found to maintain freshness is to follow a schedule of replacement. Since most products do not have clearly marked expiration dates on them, I write the month and year of purchase on the container. Herbs should be discarded and replaced after one year. Ground spices within two years, and whole spices within 3 years.
Herbs & spices should be stored away from heat, light and moisture. I know it is convenient to have your rack next to, or over, the stove but that is about the worst place for it. Other poor choices are near the sink or dishwasher. A nice cool, dark cabinet is ideal.
You can really improve the flavor of your dishes by taking a few minutes once a year to go through your spice rack and throw out the old herbs and spices.