Recent developments in condition monitoring technology have led to an ongoing shift from time-based maintenance (TBM) to condition-based maintenance (CBM). Although CBM allows for more effectively planned maintenance actions, its relative performance strongly depends on the behavior of the deterioration process, the severity of failures, the required setup time, the accuracy of the condition measurements, and the amount of randomness in the deterioration level at which failure occurs. The contribution of this paper is twofold. First, we review studies that compare CBM with TBM, and studies that consider the above factors in combination with a CBM model. Second, whereas existing studies confine themselves to a few examples, we perform a numerical investigation to derive insights on the effects of the various characteristics on the relative benefit of CBM. The results can be used by companies to decide what factors are most important when considering to implement CBM, and to assess whether the benefit of CBM during the operational phase outweighs the additional costs during the life cycle of equipment. This study allows for follow-up research to quantify and generalize the insights obtained, and to analyze interaction effects.