- many more meals must be ordered in or eaten out instead of prepared from scratch
- transportation cost increases, more vehicles needed which means more gas more insurance more repairs or more transit fare and now both people sacrifice possibly hours of their day to commuting
- childcare services must be paid for and transportation arranged for them
- the choice of housing now has the additional constraint of being within commute distance for the second job (along with other resources that must be obtained outside the home now e.g. childcare) often meaning less choice and higher cost
- with both partners sharing household duties evenly, neither can take on additional work as needed whether that's taking work home, staying late or working a second job. Dividing the labor so one person manages the household and the other devotes their energies to earning money allows both to be more effective at what they do. Division of labor is the cornerstone of an advanced industrial society that makes everything possible.