I totally agree with this about the geographic location

Certain areas, the northeast and California in particular, seem to have higher expenses than smaller towns, the midwest and the south. I think the number of people in the household plays a part. More people to have accidents, get sick, need school supplies, braces, etc. We are family of 3 and dd contributes to the household budget by paying rent & is paying us back for her car. (We paid cash for it.) It helps but I believe one person could live on less than what it takes to operate a household of 1, just like it’s cheaper for us than a family of 6 or 7.
I think the larger your home/property the more you need for emergencies. There is more that could go wrong when you have 3 or 4 bathrooms vs. 1 or 2. If you have acreage vs. a city lot there is more space for things to go wrong and possibly more opportunity for liability with someone getting hurt.