Often a team sets out to design a new piece of software using a domain model. At first they are focused on strategically valuable new featuresand modeling sessions clarify the new approach the business wants to take. Then they get bogged down because the work necessarily involvesother systems. The newly designed part must be integrated with an external system and this leads to loss of clarity in the design. Or itmust be integrated with a legacy system, compromising the new model. In response, the team may try to redesign more of the legacy system, and the scope expands. There are many ways this may happen, but they lead to the same place. The narrow focus on strategic value is lost, and the fresh and clear new approach to the problem is muddied. This talk will describe a few of the ways that the strategic design patterns of DDD,in particular, Bounded Context, are used to avoid these problems and make timely delivery of new software of modest scope but high value that is integrated with existing systems without being mired in the outdated models of the past.