The Supreme Court justices in the United States have a life tenure. Up until 1970, most justices served an average of less than 15 years.
The Supreme Court is the equivalent of a constitutional court in the United States. Countries such as Albania, Greece and Spain have what are called "high courts" that are separate from the other branches of government and are tasked with determining the constitutionality of laws.
Supreme Court justices are able to keep their offices during what was called "good behavior," and may serve as long as they like. Between 1970-2005, the average length of term for a justice was 26 years. Terms have become longer as life expectancy increases.