In planning a project, sufficient time should be left for production and programming revisions. There is no point having tests or trials if the development team has not the budget to carry out necessary revisions because of an over-optimistic belief that the team would get everything right first time.

Revisions called for may prove quite major and that is not only costly but deflating for a production team which had seen the end in sight of perhaps a very long and exhausting project. Particularly difficult is a situation where, in the course of a very long project, industry technical or production quality standards may have evolved. Managing such situations requires great skill and usually puts a significant time-cost burden on the project.