 The longest period of time in which one group of justices has served together occurred from August 3 , 1994 , when Stephen Breyer was appointed to replace the retired Harry Blackmun , to September 3 , 2005 , the death of Rehnquist , totaling 11 years and 31 days . From 1789 until 1970 , justices served an average of 14 @.@ 9 years . Those who have stepped down since 1970 have served an average of 25 @.@ 6 years . The retirement age had jumped from an average of 68 pre @-@ 1970 to 79 for justices retiring post @-@ 1970 . Between 1789 and 1970 there was a vacancy on the Court once every 1 @.@ 91 years . In the next 34 years since the two appointments in 1971 , there was a vacancy on average only once every 3 @.@ 75 years . The typical one @-@ term president has had one appointment opportunity instead of two . 
