Fitness is a condition that allows someone to persist, avoid serious health problems, and live longer. If fitness is lacking, decline and decay may ensue. In the case of libraries, fitness translates to increased longevity and less chances of failure that lead to irrelevance. In contrast to fitness in individuals, fitness in libraries is an ambiguous concept. One may point to the numbers, such as an increase in circulation or the delivery of more instruction sessions, as signs of a fit library. However, fitness is achieved by means of a combination of strategies involving discipline, commitment to change, consistent behaviors, and having fun. This article looks at several strategies that libraries can adopt to make themselves fitter and future-proofed. Adapted from the source document.