We build our software with a focus on Continuous Integration and quick deployment lifecycles. Naturally, speed is a critical component, allowing faster iterations and quick feedback.
Going from a 20 minute build to a 11 minute build time on our CI servers makes a dramatic difference in day-to-day work on our android app. The quick build time helps us stay focused and sharp. We've still got a long way to go until we get to a build time we're happy with, but we've made some good steps in the right direction.