Fuck, licensed physicians can practice medicine until the day they die. Key word, licensed. Mandatory retirement age ought to be 60, just like with airline pilots. If you're "too old" to fly a plane, you're too old to practice medicine, too old to practice law. And FAR too old to be sitting on the highest court. There's a federal district judge appointed by JFK who just officially retired. Tenure was from 1962 up until 2 weeks ago. 48 years. He's the longest serving district judge but not the longest serving judge. Several Circuit judges served for 50+ years and there's still Nixon appointees on circuit courts.