“This single team finds it easy to communicate about proposed changes and refactorings, and typically has a good sense of ownership. Now let’s imagine a different scenario. Instead of a single, geolocated team owning our catalog service, suppose that teams in the UK and India both are actively involved in changing a service — effectively having joint ownership of the service. Geographical and time zone boundaries here make fine-grained communication between those teams difficult. Instead, they rely on more coarse-grained communication via video conferencing and email. How easy is it for a team member in the UK to make a simple refactoring with confidence? The cost of communications in a geographically distributed team is higher, and therefore the cost of coordinating changes is higher. When the cost of coordinating change increases, one of two things happen. Either people find ways to reduce the coordination/communication costs, or they stop making changes. The latter is exactly how we end up with large, hard-to-maintain codebases.”