Agile projects are showing greater promise in rapid fielding as compared to waterfall projects. However, there is a lack of clarity regarding what really constitutes and contributes to success. We interviewed project teams with incremental development life cycles, from five government and commercial organizations, to gain a better understanding of success and failure factors for rapid fielding on their projects. A key area we explored involves how Agile projects deal with the pressure to rapidly deliver high-value capability, while maintaining project speed (delivering functionality to the users quickly) and product stability (providing reliable and flexible product architecture). For example, due to schedule pressure we often see a pattern of high initial velocity for weeks or months, followed by a slowing of velocity due to stability issues. Business stakeholders find this to be disruptive as the rate of capability delivery slows while the team addresses stability problems. We found that experienced practitioners, when faced with these challenges, do not apply Agile practices alone. Instead they combine practices—Agile, architecture, or other—in creative ways to respond quickly to unanticipated stability problems.