Why is it important for the US Supreme Court to be careful in overruling its previous decisions?

Answer 1

The US Supreme Court realizes that precedent needs to be respected and considered very carefully in new decisions in order to prevent social and institutional chaos. Supreme Court decisions may form the foundation of laws or be interwoven into other cases that rely on the precedent standing. Overturning an earlier decision may have a broad impact not just on the case at bar but on policies, laws, and future cases.

The overturned precedent may also have been established to prevent some form of corruption or abuse of a system (political, economic, etc.) which would then become vulnerable to manipulation.

This is one of the primary reasons the legal system relies on the doctrine of Stare decisis (Latin: Stare decisis et non quieta movere), meaning "let stand what has been decided." This principle compels lower courts to base decisions on precedents set by higher courts, with final judicial interpretation resting in the hands of the Supreme Court.