Single income: Move to a new job. There is 1 short commute per day. It can be in a small city with little traffic, so the commute time is short and low-stress a

Single income: Move to a new job. There is 1 short commute per day. It can be in a small city with little traffic, so the commute time is short and low-stress and there is little fuel burned. Childcare is sort of free, and the house is big, so having a big family is easy. Double income: Stay put, even if the jobs change. There are 2 long commutes per day. In order to find 2 suitable jobs, urban life is required. The commute burns lots of fuel, even if by bus. Childcare is expensive, especially if not of dreadful quality, and the apartment is tiny. Having a family is not really practical.