The details changed throughout the 26 decades of Tokugawa rule, but generally, the requirement was that the "daimyōs" of every "han" move periodically between Edo and his fief, typically spending alternate years in each place. His wife and heir were required to remain in Edo as hostages while he was away. The expenditures necessary to maintain lavish residences in both places, and for the procession to and from Edo, placed financial strains on the daimyo, making them unable to wage war. The frequent travel of the daimyo encouraged road building and the construction of inns and facilities along the routes, generating economic activity.