Rework is one of the four types of development activities along with Planned, Unplanned and Continuous Improvements. On average, a software development team reworks about 26% of its code prior to a release. Research indicates that the lack of proper software testing and code review are the largest contributors to rework. Don’t assume mob programing, better requirements and collaboration will reduce the amount of rework. It may be the nature of how work flows across your organization.