David Rubin has a tidy office within Metuchen, N.J., where a secretary reports every day, and he has no immediate plans to change that arrangement. But Rubin is behind the wheel of his Prius, as often as — if not more so — than he is behind his desk.

Though he drives 35,000 miles a year on business, meeting with clients or heading to court, he is never out of touch with his clients, thanks to his smartphone and other devices.