The concept of sufficiency in the context of consumption and lifestyles is based on having and doing “enough” for a good life, for what matters. Here, “enough” is both the opposite of “excessive” or “wasteful” – creating a sense of a ceiling – and a synonym for “adequate” or “appropriate”, creating a floor. As consumption choices are connected to diverse effects related to natural (i.e., energy, material, water, land) and human resources, they collectively exceed planetary boundaries, endangering livelihoods and the earth’s sustainability. Thus, sufficiency specifically asks for a reduction in wasteful consumption through lifestyle and behavioral changes, driven by both individual actions and institutional changes (see Behavior Change, Choice Editing, and Product-Service Systems). At the same time, many people worldwide still lack adequate access to services and goods for their livelihoods.