The longevity of tools and parts under steady-state conditions is governed by the microstructure and its alterations under loading. Thus, the detailed knowledge of e.g. the incipient microstructure of metals as a results of the chemical composition of an alloy, the production processes chosen as well as their sequence and parameters are mandatory to understand any properties. Still such microstructures will change under any loading, which adds the necessity to know those as well in order to understand the behavior and – if insufficient – gain well-aimed optimizing measures instead of trial-and-error approaches. Under tribological loading surfaces undergo high contact stresses locally, which by the ongoing relative motion of the bodies might generate nanocrystalline shear bands, while further away from the surface multiaxial cyclic stresses act on the microcrystalline base material. Thus, at very small wear rates within the so-called sub- or ultra-mild wear regimes, which are substantial for the longevity in practical applications, the microstructures that would allow for sufficient endurance are often a combination of some µm thick nanocrystalline shear bands as mixtures of constituents of the interfacial media (e.g. lubricants), the environment and reaction products of them. Such nanostructured composites generated by the elements of the tribosystem are called tribomaterial or 3rd-bodies. They might contain metallic, organic and ceramic constituents, while their nanoscopic structure allows for extreme shear rates and protects the underlying microstructures from catastrophic failure. Still the near-surface materials are fatigued over a long period of time and must adjust their micrometer-sized grains as well in order to sufficiently support the tribomaterial at the surface. Thus, the understanding of the small wear rates relevant for practical applications requires the precise knowledge of the microstructures of the elements (body, counterbody, interfacial medium, environment, wear particles, reaction products, …) of a tribosystem before, during and after loading. Such understanding is based on analyses over several orders of magnitude; going step-by-step from m, to mm, to µm and to nm. This contribution will show and explain some examples from the areas of biomedical engineering, which point towards the fact that without microstructure you can show everything but explain nothing.