Part of a series of time-bounded binary questions on who will die/retire from SCOTUS, because many-outcome perimutuels are bad for early predictors. It ends at the end of 2024, because any later would give Biden no chance of replacing them during his first term.
Alito: https://manifold.markets/JonathanRay/will-samuel-alito-leave-the-supreme
Thomas: https://manifold.markets/JonathanRay/will-clarence-thomas-leave-the-supr
Roberts: https://manifold.markets/JonathanRay/will-john-roberts-retiredieleave-th
Actuarial tables give a 68 year old a 2.5% chance of dying by then https://www.ssa.gov/oact/STATS/table4c6.html, but you might adjust that upward due to obesity, and voluntary retirement is possible considering her ideological alignment with Biden and uncertainty about who will replace him.