HOW THEIR QUEST BEGAN: In 2007, Lim started researching how refinancing his home-equity loan might affect his number -- and got hooked on the credit scoring mystery.
WHAT HE'S LEARNED: To be vigilant. He regularly scans his credit reports for errors, makes sure he doesn't have too many credit cards reporting balances, and stops charging before applying for new loans.
THE PAYOFF: "My wife thinks I'm crazy," Lim says. "But we got great interest rates on our car loans and our HELOC."
NEXT: Chris and Chrissy Peplinski