Zastrow and Kirst-Ashman (2016) stated, "We need theories to guide our thinking and our work so that we may undertake research-informed practice" (p. 127-128). At the same time, the authors asserted, "No theory will be perfectly applicable. Perhaps you will decide that only one or two concepts make any sense to you in terms of working with clients" (p. 128). Though you may be able to apply only a few concepts in a particular theory to your work with clients, as a social worker, you should be applying evidence-based research to your work. Empirically-based developmental theories may guide you as you assess clients and their presenting problems. You may also apply developmental theories to your treatment decisions.