Dysfunction of mitochondria has severe cellular consequences and is linked to ageing and neurodegeneration in human. Several surveillance strategies have evolved that limit mitochondrial damage and ensure cellular integrity. Intraorganellar proteases conduct protein quality control and exert regulatory functions, membrane fusion and fission allow mitochondrial content mixing within a cell, and the autophagic degradation of severely damaged mitochondria protects against apoptosis. Here, we will summarize the current knowledge on these surveillance strategies and their role in human disease.