Applying a set term to Justice's tenure will greatly reduce the amount of time a justice is in any particular role. Once we have those terms in place, no justice will be sitting there for 40 years without any further discussion of their fitness for office. Even if we allow justices to be re-nominated for more terms, they would at least be subject to another Senate vote.

But your comment about their finances is a whole different matter. Did you know that the SCOTUS justices are not formally bound by any code of ethics? There is a code imposed on lower court justices, and SC justices tend to follow those because they were all lower court justices at one point, but they have no formal accountability to anyone but themselves. Congress has threatened to withhold their funding if they don't adopt a formal code of ethics, but that hasn't gone anywhere.