Supreme Court justices have life tenure, and so they serve until they die, resign or retire, or are impeached and removed from office. For the 105 non-incumbent justices, the average length of service was 6,203 days (16 years, 359 days).
The average tenure for Supreme Court justice has been 16 years. However, some associate justices have served for as long as 36 years (William O Douglas), and as short as just over 5 months (Thomas Johnson
