Adaptation to illness, and its relevance for distribution in health care, has been the subject of vigorous debate. In this paper I examine an aspect of this discussion that seems so far to have been overlooked: that some illnesses are difficult, or even impossible, to adapt to. This matters because adaptation reduces suffering. Illness severity is a priority setting criterion in several countries. When considering severity, we are interested in the extent to which an illness makes a person worse-off. I (...) argue that no plausible theory of well-being can disregard suffering when determining to what extent someone is worse-off in terms of health. We should accept, all else equal, that adapting to an illness makes the illness less severe by reducing suffering. Accepting a pluralist theory of well-being allows us to accept my argument, while still making room for the possibility that adaptation is sometimes, all things considered, bad. Finally, I argue that we should conceptualize adaptability as a feature of illness, and thereby account for adaptation on a group level for the purposes of priority setting. (shrink)