I've often heard as a rule of thumb that if you have both, go with fresh. But are there exceptions to that? Are there times when using dried herbs is preferred?
Using one or the other can depend on how long a dish is cooking. Dried herbs take a while to impart flavor so they're mostly useful for longer cooking dishes. Also, getting a piece of dried herb that hasn't had time to hydrate & soften can be really offputting to eat! Often, however, I use both- dried or sturdier herbs at the beginning & fresher/more tender herbs at the end when the dish is pulled off the heat. That way you get layers of flavor, not just top notes.