What should the term limit of a supreme court justice be?

I have been giving this alot of thought and I just cant concieve that the shrub gets to appoint two life time appointments to the supreme court. So I was wondering if you were given the option how would adjust the term limit to the supreme court? I.E. every two years or four years or something else together?

Long enough to be stable, not so long that it affects the next frickin' 20 generations of Americans.

Life terms were originally intended to insulate the SCOTUS from any temporary political shifts of power. Only political shifts of power that proved significant have lasted long enough to appoint enough justices as others retired to affect the make-up of the court. The Warren Court was a significant achievement, for instance. Without that, Jim Crow would have lived longer than what it actually did after Brown v. Board of Education.

Remember that if you change the rules, the rules also apply to you as well.

The only change I would make is some sort of senility rule. If you're no longer mentally or physically able to perform the duties of your court, you should be made to retire.