Spices don't last forever, and fresher is better. If you have a few spices you don't use all that often, make sure they haven't lost that flavour with this cheat sheet.
Graphic by Vicky Wasik at Serious Eats
Whole spices tend to last longer, while dried herbs, flowers and zested citrus lie on the shorter end of the spectrum. You may get a slightly longer shelf life than quoted in the sheet, but freshness will usually start to decline after a few months.
Check out the chart below and if you haven't given your spice drawer a good cleaning in a while, now may be a good time!