Allan Ross wanted to buya second home. But the chief executive of a Canadian oil and gas research business was having trouble deciding where he wanted it to be. At 50, he had also developed an aversion to certain things that go with home ownership.

"I'm not good at cutting grass or putting salt in the salt shaker," he says, chatting from a $2.5m pied à terre that overlooks Central Park in Manhattan. Twenty-five stories up, in a two-bedroom flat with 21 ft ceilings and a balcony, he does not worry about such mundane chores: "I just show up."