1. witch is useless when the main structure reach the end of life... And it's useless for energy saving purposes, because you can't change the overall design to

1. witch is useless when the main structure reach the end of life... And it's useless for energy saving purposes, because you can't change the overall design to get more low Sun in the winter and less high Sun in the summer and so on. Rebuilding means demolishing the whole structure to create a new one, with a different design for different purposes; 2. I was in Tokyo for a project and before as a tourist, I've not seen large buildings totally erased and rebuilt but it doesn't matter I was there for a too little timeframe for that, but enough to see how many issues of high density Tokyo have, even the the Japanese have put an immense effort to handle many of them. About the lifestyle I suggest, here in EU: - Nederland, 425.4 humans/km², 81.3% live in single family homes - Belgium, 381.79 h//km², 77.6% in single family homes - France, far less dense, 62% in single family homes - Ireland even less dense, 89.4% in single family homes While some others like Italy or Spain do the opposite. Accidentally I'm Italian and I'm living in France switched from a dense city to the mountains and have no intention to came back, as many, many others, essentially all that have tried this way, so well, working it does work, it's not crazy, and local services are spread as well offering local jobs to many people in far better living condition than dense cities in the same country. It's a matter of choice, and I bet the late night Tokyo metro show the effect of density on humans.