Condition-Based Maintenance (CBM) appeared in the eighties as a response to avoid unnecessary maintenance and its related economic and time implications. Many techniques, based on the asset's condition, to determine the adequate moment to perform maintenance actions have been developed, using a wide variety of tools. However, CBM is not actively applied by managers or companies. An in-depth literature review using the State of the Art Matrix (SAM) analysis methodology is applied to the CBM literature to understand the reason for poor CBM implementation. In addition, the critical areas of future CBM research are explored and analyzed to assist industrial engineers and managers to better comprehend the current state of CBM applications and research opportunities.