Following a brief review of the evidence available at the time, Christensen and Jacobson (1994) concluded that professional training was unwarranted on the basis of client outcomes. As a result, they advocated for psychologists to focus on program development, training, and supervision while promoting an expansion of paraprofessional-, peer-, and self-administered mental health services. In this updated and expanded review, we focus more narrowly on prepracticum and practicum training in doctoral health services psychology and examine the evidence more closely. At the omnibus level, we conclude that evidence for training-as-usual remains lacking. However, closer inspection reveals effective training methods that significantly improve important psychotherapy elements (e.g., relational competencies;Hill et al., 2015) and client outcomes. After review of the empirical literature, we conclude that (1) training-as-usual is insufficient, (2) selection of individuals for training may be of critical importance, (3) training can produce measurable effects, and (4) those changes are both directly and indirectly associated with reduction of attrition and improved client outcomes. Rather than concluding that training is unwarranted, we conclude that training merits evidence-based augmentation.