It is declared to be the state’s public policy that chancery and circuit court judges and justices of the Supreme Court may retire or be retired when that course appears to be in the best interest of the official concerned and for the public welfare. Factors suggesting the desirability of retirement are physical disability, advanced age, or other infirmities calculated to materially impair usefulness. In addition, it is the public policy of the state to provide sufficient retirement and survivors’ benefits for the chancery and circuit court judges and justices of the Supreme Court of the state to attract and retain highly capable members of the legal profession for service in the state judiciary.