You'll always fail first. Imagine starting your own company, creating a life-changing, world-saving product, and pouring every dollar, minute and ounce of sanity into cultivating your business. Imagine then realizing one day that your product is in some way irrelevant or unmarketable. What do you do? Sure, you could give up. But Tom Szaky, the CEO of TerraCycle, says it's easy—just change your business model and keep going. Szaky writes in The New York Times' You're the Boss column today about how his company survived its first, second, third and fourth business models and still remains open to more changes. Because in business, there's always room for a plan D.