As firms like REWE Group and Schneider Electric have learned, digital experience strategy shapes the technology you need — an investment that can take five years and cost between $20 million and $200 million. To help define the strategy, application development and delivery (AD&D) professionals should follow the lead of customer experience teams: 1) Start with a customer journey map; 2) apply cloud-hosted, mobile-first, and insights-driven thinking; and 3) implement a digital experience platform to serve customers along every step of their journey. This is an update of a previously published report; Forrester reviews and updates it periodically for continued relevance and accuracy.