Advantages:

• Encourages analysis of alternatives.

• Allows the scope of the project to grow.

• After each loop, assesses what you have done and allows the project scope to change.

• Allows deployment of a basic system first, with extra functionality delivered later.

• Accommodates the reality that many requirements are not known until after a system is deployed.

• Allows customer feedback to become part of the design process.

• Each loop can use any SDLC.

Disadvantages:

• Overhead of analysis and release for each loop adds extra time.

The disadvantages of Spiral can become critical if too many interim releases are planned. In that event, using an Evolutionary or Incremental Life Cycle within a Spiral is recommended.