From an interview with designer Luke Wroblewski:
What’s his secret? Data and intuition, he says, should “complement each other, not compete.” The way to put that maxim into action is to forget about aiming for some objective bulls-eye of perfection–all due apologies to Steve Jobs–and treat the act of creation as a continual learning experience that empirical research and gut instinct both inform.
“The more tangible, real-world data you drink, the more you fill your gut with the right kind of instincts,” Wroblewski says.
How do you know when a design is really done (Fast Company)