Bearings are used in machines and devices to guide components that are moving against each other. Depending on the application, different degrees of freedom are allowed, which define different types of bearings. In addition, a differentiation is made between plain bearings and roller bearings. While the parts in a plain bearing that are moving relative to each other have direct contact with each other, they support themselves in a roller bearing by means of revolving roller bodies. Both types are used in pumps, and a comparison shows that both have advantages and disadvantages. Roller bearings show less friction and more accuracy, but they are also more sensitive to impacts, more expensive and continue to wear even if they are not in operation.