I would say that the ordinarily very useful abstraction of subjective probability breaks down in situations that involve copying and remerging people, and that our intuitive morality breaks down when it has to deal with measure of experience. In the current technological regime, this isn't a problem at all, because the only branching we do is quantum branching, and there we have this neat correspondence between quantum measure and subjective probability, so you can plan for "your own" future in the ordinary obvious way. How you plan for "your own" future in situations where you expect to be copied and merged depends on the details of your preferences about measure of experience. For myself, I don't know how I would go about forming such preferences, because I don't understand consciousness.