Can One Tell How Old Dried Herbs Are?

Can the age of the herbs ordered be ascertained? I want to know how potent they are and that they are fresh and effective enough to be used for medicinal purposes. The herbs bought at a health food store sometimes are years old and do not smell like they are potent enough.

There is no simple way to tell how old dried herbs are. The most accessible way is to look at the colour of the herbs. Dried leaves, whole herb, and flowers that have been in storage for long will often fade in colour. Instead of nice green leaves, the leaves may be pale green, yellow or brown. Smell and taste can be clues too. Aromatic spices will lose their characteristic odour and flavour over time, and some medicinal herbs such as catnip and chamomile do the same as they age.
Chemical analysis is used by large commercial buyers of herbs and spices to judge quality, and so indirectly they can often guess the age of herbs. Consumers, however, must rely on their own senses or must purchase from a reputable supplier that does not keep herbs in inventory for more than a year or two.
Quality is not a direct determinant of age. Poor quality does not come from aging only. If herbs are improperly harvested and dried, or improperly processed and stored, they can be much worse than quality herbs that were stored properly in a cool, dark place for five years.