Software development methods vary. To understand how an approach will impact the development process, there are three constraints that need to be considered:
- Budget: The total amount of invested capital
- Scope: The features and capabilities of the project
- Schedule: The deadline or time allotted for “going live”
The iterative development process can be used if one of these constraints is flexible instead of rigid. In the case of a fixed budget or fixed price project, either the scope or the schedule needs to be flexible.