Currently the Supreme Court has lifetime appointments, and Congress members can keep running as long as people will vote for them. I propose an amendment that ties the retirement age for all branches of government to the national retirement age.
For elected positions, you can't run if you are over the national retirement age, if you reach the retirement age during your current term you must retire at the end of your term. For appointed positions you must retire at the end of the current session once you reach the age of retirement.