Although carburization is a relatively well-known phenomenon, the best method for evaluating the total carburized depth remains a question for end users. It was observed that some standard documents do not include or recommend hardness traverse testing as a method for evaluating the carburized/hard layer, and when they do, they do not address the method of determining the total case depth. Two objectives were pursued in this investigation. First, to present a literature review on carburization in a practical, topic-based format, which includes all relevant topics from description and mechanisms to evaluation and prevention. Second, to discuss different methods of evaluating the carburized depth, particularly the total depth on a hardness profile or a carbon concentration profile. Two procedures, namely, linear regression and curve fitting, are compared, and offset values (10 HV on a Vickers hardness profile and 0.05 wt% on a carbon concentration profile) are proposed for total depth determination upon curve fitting. One of the case studies presented demonstrates that sometimes a significant transition zone can form between the bulk carburized layer and the core. A distinction is also emphasized and clarified between the depth of carburization and the extent/degree of carburization as criteria for evaluations.