Who decides? The voters?
The President with Senate confirmation of a reappointment or removal. They’d have to have a time frame without which it would go to a House vote.
I’d like to see them staggered like Senators, so 3 years for 9 Scotus justices...therefore 3 years for all lesser courts.
I also like to see them better regionalized. The current court, believe it or not is: 5 New Yorkers, 2 New Jerseyites, 2 Californians, and one Georgian.
They definitely snubs its nose at flyover country.
Sorry...4 New Yorkers