Term limits for Supreme Court Justices?

Sandra Day O'Connor remarked the other day that she left the Supreme Court earlier than she would have liked:

Retired Justice Sandra Day O'Connor would have preferred to stay on the Supreme Court for several more years, but she stepped down because of her ailing husband. "Most of them get ill and are really in bad shape, which I would've done at the end of the day myself, I suppose, except my husband was ill and I needed to take action there," O'Connor said.

Look, I don't want justices to have to take tests every year or something to prove their competency, but I don't know if I'm comfortable with this lifetime appointment thing when they absolutely come hell or high water refuse to retire.

The article goes on:

As a retired judge, O'Connor maintains an office at the Supreme Court, still draws a salary and occasionally sits as a judge on the federal appeals courts.

She's doing all right.

Here are some judge fun facts.