Answer:
Collegiality
Justices can serve on the Supreme Court for life, so it's vital they get along with and respect one another. But collegiality also serves another purpose: This quality can help a judge bring another justice to his or her side during a case, experts told Live Science.
Varied backgrounds
Presidents once nominated justices with diverse backgrounds, choosing senators, law school professors and prominent attorneys. However, ever since Richard Nixon's presidency, most of the nominations have been judges from lower courts, largely because these individuals appear easier to confirm than non judges. For instance, justices need to be mindful of how cases play out in the real world, as a politician would.
