Many regulatory agencies are structured so as to be insulated from the president and, in theory, from political pressures. They are run by independent boards whose members are appointed by the president and must be confirmed by the Senate. By law, these boards must include commissioners from both political parties who serve for fixed terms, usually of five to seven years. Each agency has a staff, often more than 1,000 persons. Congress appropriates funds to the agencies and oversees their operations. In some ways, regulatory agencies work like courts. They hold hearings that resemble court trials, and their rulings are subject to review by federal courts. Despite the official independence of regulatory agencies, members of Congress often seek to influence commissioners on behalf of their constituents. Some critics charge that businesses at times have gained undue influence over the agencies that regulate them; agency officials often acquire intimate knowledge of the businesses they regulate, and many are offered high-paying jobs in those industries once their tenure as regulators ends. Companies have their own complaints, however. Among other things, some corporate critics complain that government regulations dealing with business often become obsolete as soon as they are written because business conditions change rapidly.