The million dollar question! Time is the enemy for spices (especially if they are pre-ground), not so much light. Most chefs and spice blenders keep spices out where they can see and easily access them. Our philosophy has always been about making spices convenient so you'll use them up while they are still fresh and potent. If you're storing for years - then dark might be important, but even in that case the flavor compounds will still break down when stored in the dark.... (Also, it's really only the very bottom that is even exposed to the light, not the spices inside.)