DC-DC converters are becoming more commonly used in power conversion solutions for energy management purposes, being employed in an ever-increasing range of DC-based applications, such as LED lighting, electric vehicles, energy storage solutions, and consumer electronics (laptops, smartphones, etc.). In this context, efficiency and reliability are critical. The research efforts made in improving reliability of DC-DC converters are still quite narrow and scattered. Moreover, DC-DC converters take the shape of an endless number of topologies, with different functionalities and operation principles, thus complicating the task of improving reliability of all forms of DC-DC converters. Consequently, compiling the information about the main failure modes, corresponding fault diagnostic algorithms and fault tolerance strategies developed so far, in a single document, becomes increasingly necessary. Accordingly, this paper presents an up-to-date review of the recent achievements attained regarding the improvement of availability and reliability of DC-DC converters.