They are not interchangeable, and knowing when to reach for the jar versus the bunch will sharpen everything you cook.
Fresh and dried herbs are different ingredients that happen to share a name. Drying concentrates and changes an herb, driving off the volatile, grassy top notes and leaving something earthier and more potent. Treating one as a substitute for the other is where a lot of home cooking quietly goes wrong.
As a rule, hardy herbs dry well and belong early in the cooking. Oregano, thyme, rosemary, and bay give their best when simmered into a sauce or braise, and the dried versions are often more useful than fresh because their flavor is concentrated and stable. Add them at the start and let time draw them out.
Delicate herbs, on the other hand, live in the last minute. Parsley, dill, mint, basil, and cilantro lose everything that makes them worth eating if you cook them, so stir them in off the heat or scatter them over the finished plate. A dish can take both: dried oregano in the pot for depth, a shower of fresh parsley on top for lift. Keep the hardy ones in the cupboard and the tender ones in a glass of water on the counter, and use each where it belongs.
