According to one prominent view of exercising abilities, a subject, S, counts as exercising an ability to ϕ if and only if S successfully ϕs. Such an ‘exercise-success’ thesis looks initially very plausible for abilities, perhaps even obviously or analytically true. In this paper, however, I will be defending the position that one can in fact exercise an ability to do one thing by doing some entirely distinct thing, and in doing so I’ll highlight various reasons that favor the alternative (...) approach I develop over views that hold that the exercise of an ability is a success notion in the sense Millar maintains. (shrink)