An SDLC is meant to provide a flexible set of guidelines that can be adapted to any project by tailoring the steps, processes, and procedures to meet specific needs. To tailor the life cycle, the project team may decide to combine project phases; omit, combine, or reduce steps, tasks, or work products; or require added or different tasks or work products as appropriate. The Project Manager should consider the size, complexity, and scope of the project when making any decision to tailor an SDLC and all such decisions must be documented in the project notes. The tailored process must include an Initiation Phase which bases much of the information gathering on the approach to satisfying the business need or opportunity. There are essential tasks and work products that cannot be “tailored out” even when third parties provide a separate SDLC or methodology. For example:
- Clear functional requirements are needed.
- The resulting system must be able to operate within OIT's and the functional unit's current and planned IT infrastructure and architecture.
- A determination of the feasibility of the project and a look at possible alternatives, including continuing with the status quo.
- Systems must be adequately tested.
- Users must be adequately trained.
- Proper documentation must be available to allow users to operate a system as it was intended.
The phases described in the SDLC are not intended to constrain systems development such that one phase must be completed before another phase begins. Many phases and steps may be ongoing at one time. The documents described in the SDLC provide a recommended order to guide those responsible for procurement, development, implementation, and maintenance.