There did seem to be some pressure to have Anthony Kennedy retire as Supreme Court Justice to get the younger Kavanaugh confirmed right before the 2018 midterms in case the Republicans lost control of the senate.
He served 30 years on the Supreme Court, so it made sense to retire and I don't like these lifetime appointments where they hang on until death (sorry Scalia and RBG).
But if you had an exact term length, like 20 years, you couldn't have any of these moves where they try to time new SC members to when the same party holds both the White House and the Senate.
By the way, Kennedy was confirmed in 1988 (a presidential election year) with a Republican President in his last term and a Democrat majority Senate.
It's the same scenario of the 2016 Garland nomination but with a Democrat President in his last term and Republican Senate.
The Democrat senate confirmed Regan's choice but the McConnell Senate would not hold a hearing or vote on Obama's choice who even Republicans voiced was a good moderate choice.
A 20 year term beginning and ending in odd years would work to end these political dances.