Although a tacksman generally paid a yearly rent for the land let to him (his "tack"), his tenure might last for several generations. He would often be related to his landlord and might, for example, represent a
cadet branch of the family of the
clan chief. The tacksman in turn would let out his land to sub-tenants, but he might keep some in hand himself.
Samuel Johnson defined the class in this manner: The three fundamental obligations traditionally imposed on tacksmen were grassum (a premium payable on entering into a lease), rental (either in kind, or in money, which was designated "tack-duty"), and the rendering of military service. ==Inheritance==