Surprising Cost Curve

One of the surprising and pleasant effects that the incremental method can have is that the cost of some functionalities decreases over time. The following factors can cause this.

• Well-designed (refactored), simple code in which no duplication is allowed often presents the developer with opportunities to reuse significant parts of the code, which makes new features easier to implement.

• Over time we learn to better understand the problem domain, the design, and the software. We see new abstractions, simpler ways to solve problems, and better ways to apply our designs.

So, we find another heuristic for selecting the incremental method: Use the incremental method when you expect to learn more so that you can make better decisions later. This applies especially to situations where requirements are unclear or changing.