I individuate two dimensions along which abilities can be robust. Dimension I distinguishes the successful exercise of abilities, which requires local control, from cases of lucky success. Dimension II concerns the global availability of relevant acts, which ensures that an agent has the option to perform some act across a variety of scenarios. I show how this framework resolves a point of tension in the literature regarding the strength of the robustness required for ability and explain how it provides insight in the relation between ability possession and exercise.