I say yes. 2 10-year terms max, with approval by the Senate each time. This also enables them to outlast any president that appoints them, so it maintains some freedom, if they choose to use it.
But we can't have people like Scalia throwing his weight around for 30 years, and do you think John Roberts would be pulling his garbage if he was in danger of losing his job next year? Of course not.
OK Baggers, you want a new Constitutional convention? Then start with this.