Betsie's job was to work in the watch shop, doing the books and helping with customers.  Corrie's job was to take care of the house.  The two sisters originally traded jobs because Betsie, who had always had health issues, caught a cold, and "Father decided that she must not sit behind the cashier's table where the shop door let in the raw winter air".  The switch was supposed to be temporary, just until Betsie got better, but, to their surprise, both women found that they were better suited for the other's job!  Corrie found the office records in a shambles, and quickly put her natural business and organizational expertise to work straightening them up.  And Betsie found numerous ways in which the house and its running could be beautified and improved, and spent her days doing little things to bring out the natural beauty of the old rooms and concocting all kinds of interesting and innovating things for the family to eat. 

Both Corrie and Betsie felt guilty about the joy they found in each other's jobs, and resolved that soon they would return to their old roles.  Imagine their delight when each discovered the truth - that Corrie thrived working in the office, and Betsie wanted nothing more than to spend her days in complete charge of the running the household.  The sisters made the trade permanent, and both flourished in their new occupations (Chapter 4).