Companies must think through what complementary assets, capabilities, products, or services could prevent customers from defecting to rivals and keep their own position in the ecosystem strong. Apple designs complementarities between its devices and services so that an iPhone owner finds it attractive to use an iPad rather than a rival’s tablet. And by controlling the operating system, Apple makes itself an indispensable player in the digital ecosystem. Corning’s customer-partnering strategy helps defend the company’s innovations against imitators: Once the keystone components are designed into a customer’s system, the customer will incur switching costs if it defects to another supplier.