Practitioners in youth settings experience life on the ground as a tumble of events, shaped by a confluence of youth needs, institutional expectations, and other inputs. The quality of the setting is determined in part by practitioners' expertise in shaping and responding to these events. The situations that arise in practice, and how staff respond, can be turning points, good or bad, in youths' experience of the setting. They can also be opportunities for youth development. This article examines the wide-ranging events, situations, or "dilemmas of practice" that occur in the daily life of youth development programs. Research shows that these varied situations are shaped by the ecology of diverse people and systems that influence the setting. They involve considerations that may entail everything from the psychology of different youth, to how parents from a cultural group think, to the dynamics of government systems. Expert youth practitioners, it is found, are able to identify more considerations than novices in these situations, and they possess a wider repertoire of responses. They also formulate more responses that are youth centered and address multiple considerations. Expertise involves being able to balance diverse concerns, including how to create and sustain conditions for the development of young people. Researchers can contribute by helping us better understand this array of situations and how experts respond. Improvement in the quality of youth settings can be achieved through greater knowledge of the tumble of events that occur and by helping train practitioners in skills for responding to it. (Contains 11 notes.)