We all do it, keep spices too long, then wonder why our dishes don't have flavor.
Dried spices, in general, are good for about 6 months stored in small glass jars. Some will last longer if you store them in a dark place until used. I go through my spice drawer once a year to re-organize the jars. They start out the new year cleaned out, in alphabetical order, with a list of which ones I need to buy fresh.
By the end of the year, the drawer is a mess but I still know which ones to replace, and which herbs I need to grow. To keep track of jars, I write the date I bought it on the glass jar bottom so I can easily determine which ones are out of date. Don't throw them away; you can compost dried spices.
What is your favorite spice?