But as the dimensions of private homes in some parts of the city have grown — from 8,000 to 20,000 to 30,000 and even 40,000 square feet — the lots on which they sit haven't gotten any bigger. In the flats of Beverly Hills and north of Montana Avenue in Santa Monica, where 5,000-square-foot starter castles occupy lots meant for much smaller homes, people can lean out their windows and chat with neighbors, as their grandparents living in big-city tenements perhaps did. Space, not within vast closets or indoor bowling alleys but around sprawling houses, might be the last great luxury.

I paid $ 131,000 for my starter castle. I lived there for three years. I can document $ 10,000 of home improvements, bringing my total to $ 141,000. Add another $ 8,000 in closing costs, and I invested $ 149,000. I sold for $ 102,000. That's a loss of $ 47,000 - more than triple my $ 13,100 down payment and enough that if invested conservatively today would put at least one of my children through college when the time comes.