In Al-Riyadh city there are 2 different types of residential blocks. First, single houses. Seconds, apartments. They used to be only single houses and it was really big houses with a size of 400-1200 square meters. But now they have becomes a small one with a size of less than 200. Also, the apartment used to be bigger, but now they become smaller. you need to investigate that in the old suburb and new ones, also in the new neighborhoods. you also need to look for the answer to why these new residential blocks have smaller houses and smaller apartments. Also, what is the cost of buying one (house, apartment) in a different area because of the process will vary. The most important is the following. 1- blocks size. 2- blocks design. 3- houses and apartment sizes and designs. 4- the percentage of public open space and parks in these blocks. 5- the road size and speeds.