To explore costs and benefits of part-time work for high school students, survey responses of high school seniors from the classes of 1980 through 1984 were examined, distinguishing between those working many hours, those working fewer hours, and those not employed. Because hours of work differed by sex and by college plans, most analyses controlled for those factors. Work intensity, or number of hours worked, was positively related to perceptions of stress and interference with social life, but also to perceptions of increased contact with those of other ages and social backgrounds, as well as with the acquisition and use of skills. Most high school seniors saw little or no connection between their present work and their long-range aspirations. Substantial portions of earnings were spent on discretionary items. There was weak evidence supporting the view that working interfered with school. There were no relationships between work intensity and psychological variables such as self-esteem. Work intensity was positively correlated with aggressive and delinquent behaviors; victimization; and use of cigarettes, alcohol, marijuana, and cocaine. Although the evidence is mixed, it appears likely that some undesirable consequences are caused rather directly by working long hours in part-time jobs while still in high school. (Author/NB)