New Delhi, Sept. 7 -- Twenty years ago, Nina and Saurabh Joshi returned to India after living abroad for many years. In their early thirties and raising two young children, they began planning for the family's future.

They bought two apartments in addition to the home they lived in. Their reasoning was simple: one property for each child. They imagined that when the children eventually moved out of the family home, each would settle into one of these apartments.

On the surface, the plan seemed sensible. But it rested on an assumption the Joshis had not tested: would their children actually want these properties?

Over time, their daughter Nilima, moved to London for her undergraduate studies, while their son Nikhil relocated to Californ...