Darlene is a $100 a night call girl. If she worked every night, she would have made $36,500 in 1980 ($132,476.75 in 2024, adjusted to inflation). This is typical income for a middle-class person, but Darlene is made out to seem very wealthy, since she wears designer clothes and drives an expensive car.
During the call that Jack has with his mother and when Janet runs out of the kitchen to stop him on the phone..you can see the kitchen wall placement is flat with no sink or wall cabinet.