We could just appoint them until a given age, let's say 70 for example, and then guarantee lifetime benefits after that but they no longer serve.
It has all the same benefits of a lifetime tenure, they don't need to worry about retaliation, they wouldn't be _more_ likely to accept bribes since they will still have income and benefits for their retirement, etc.
Well, unless the person strongly values the contribution to society that being a judge represents. If there's another career they could go into and still practice into their 90s, maybe they'd prefer that.
It has all the same benefits of a lifetime tenure, they don't need to worry about retaliation, they wouldn't be _more_ likely to accept bribes since they will still have income and benefits for their retirement, etc.