How much, if at all, should we value the prospect of extending human lifespan? Some of the costs and benefits are clear, and others can be assessed empirically. But we also face various tricky axiological choice-points. For example: Are persons the fundamental units of well-being, or person-stages? Do we measure the value of outcomes with average or total well-being—or something else? Do units of time in a life yield diminishing marginal value, even if they are equally good in other respects? Which relational features, if any, matter in addition to the local features of persons or person-states? Several of the most plausible ways to negotiate these choice-points yield important structural advantages for lifespan extension.