We consider the management problem of a production system in which workers conduct their own jobs for each item. Workers take a break after a certain amount of work time and restart work. They switch with new workers after the work-recess cycle is repeated several times. To develop an optimal management policy, we develop a work-recess model and obtain a mathematical formula for the expected cost rate function per unit of work. We also demonstrate that there exists an optimal number of work-recess cycles, an optimal amount of work during a work-recess cycle and an optimal recess time, each of which minimizes the expected cost. A numerical example is presented to illustrate the proposed preventive management policy.