Foe the middle calss : Its easier and less expensive / less time consuming to maintain an apartment than a bungalow...its also more convenient to stay in a cluster than stay alone with the crime graph as it is nowadays...so maybe feel more secure in a group.
For the Elite Class: Its always a pleasure to have a bungalow of their own...with a garden...wide open spaces and a personal swimming pool...than reside in a congested apartment block...they have the money to hire efficient house helps and security...so why would they bother at all !
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Cost consiousness, and security. Apartments are cheap compared to individual hoses. Secondly security problems. Even they will be away from house,the security is more when compared to individual houses,if not no assrance will be there.