Why are there life-terms on the Supreme Court? Doesn't that incentivize the justices to hold on past their prime, dying waiting for a new president or resigning in a politically motivated fashion? And don't life terms create a race to the bottom where younger justices are favored for longer remaining life? Why not 20 year limits?
In India we have a fixed retirement age. Of course extensions can be granted on an exceptional basis, But in general you serve till a fixed retirement age and retire. It also makes sense. Cognitive ability deteriorates with age. And you don't want very old, with illness to rule on important things.
The idea behind no term limits is, the judge can choose to retire doesn't have to.
You have invested a lot of effort in getting a judge to the top as a country. you don't necessarily need a arbitrary date to retire.
Each individual has a capacity to serve upto different age unique to them. Setting a common age for all is not efficient, plenty of judges for example are employed in india post 65, in arbitration and government commissions.
It makes sense not have term limits when the court size is small.
The problem for america is that everything is political: judges and their retirement . In a 2 party first past the post/ winner takes all system that is inevitable.