Often, as deliverables are developed, change requirements surface. The earlier they are identified, the easier it is to negotiate changes to plans, contracts, and schedules. Very long tasks tend to be poorly defined and estimated, and are often work-time black holes. Each deliverable must have a client team member, knowledgeable in the deliverable's purpose and goals, sign off on the deliverable. Timely review and sign-off is as much on the critical path as development of the deliverable.
Delays cost here.
However, this should be a nonevent, as the reviewer should be involved with the developing product all along. There is often a point after which incremental investment of time or money does not pay. To ensure an objective measure of acceptability, the rules should specify what constitutes a complete, successful deliverable. It is sometimes useful to define what is not included. Type of Deliverable Criteria of Success Project Master Plan List of projects including descriptions, proposed staffing, timing, and budget for each project.