In the real world, few of us can choose how many hours we would like to work. Usually an offer is made which might allow you negotiate for the wage, but not necessarily for the hours. We will, however, assume in the following analysis that you can determine the number of hours you wish to work. In the following section, we will take a closer look at what the factors are that influence a rational individual's choice on how many hours to work.
Take the case of Kevin. Kevin needs to decide how many hours to allocate to work and how many hours to allocate to leisure. Since he is a rational individual, he will compare the marginal utility of an additional hour of leisure with the marginal utility he gets from working an additional hour.
Assume Kevin can earn a R100 per hour. What is his marginal utility he gets from working an additional hour? And what is the opportunity cost of working this additional hour? The marginal utility he gets from working an additional hour is the satisfaction he derives from goods and services he can purchase with a R100. What he gives up to earn this R100 is the loss of an additional hour of leisure. This is his opportunity cost to work an additional hour.