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An incremental model of software development life cycle


Now, let’s dig a bit into another part of software development: life cycles. We’ve already wrote about incremental model year ago, but let us remind some stuff.

As I already noted in “Why you had to maintain Game Design Documents“, keeping your documentation up-to-time, clean and understandable – is probably one of the biggest, yet wanted struggles. But there is also a question about keeping your team in one pole “on go”, cause you may guess that if 40% of current work-time would be spent on studying docs no magic will happen.

So, the incremental model means partial implementation and a slow build-up of functionality. Using such an approach you may reduce the costs of MVP product pushing.

The incremental model is most of all based on a cascade model with overlapping, so that the functionality of the product, suitable for operation, is formed before.

In incremental development each subsequent version of the system adds to the previous defined functionality until all the planned features are implemented. It helps you reduce costs, monitor the impact of changing requirements, and accelerate the creation of a functional system through the use of the standard block layout method. You may also change da wae (knuckles) of your tool according to users feedback, setting highest priority either on some suggested features or bugs that are prompted to be fixed.

Incremental model

Phases of the incremental model of the software development cycle

Early stages of the SDLC (planning, analysis and design) are usually (ideally) hoped to be able to explain the whole system design. So also the increments and related features are pre-determined.

Each increment passes through Implementation, Testing, and Deployment.

After implementation and tests of required features that form the MVP, subsequent iterations tend to extend the system core, improving its performance or adding new features. New functions implementations are carried out by performing significant increments to completely satisfy the user’s needs. Each particular feature is certified in accordance with requirements and specifications of the software.


  • Small regular payments;
  • Generates working software quickly and early during the software life cycle;
  • You can prevent the absence of cumbersome requirements lists by dividing the project into easily manageable parts;
  • You still are able to maintain progress during the implementation;
  • Lowers initial delivery cost;
  • The risk of failure and changing requirements is reduced;
  • Risks are more manageable ‘cause of project decentralization into partially-dependable pieces.
  • Requirements are stabilized via increments-provided control-points;
  • Incremental functionality is more useful and easier to test than middle-tier products with level-by-level “top-down”
  • Costs- and compliance-related risks are easily re-reviewable on each iteration;
  • The flexibility that rises on low-cost scope and requirements changing.
  • The possibility to start building the next version in the transitional phase of the previous version smooths out the changes caused by the personnel change;
  • It is easier to test and debug during a smaller iteration.
  • In this model customer can respond to each built.


Well, making incremental SDLC a wrong choice has its own consequences, related to:

  • Each increment ain’t followed by iterations;
  • Problems may arise pertaining to system architecture because not all requirements are gathered up front for the entire software life cycle;
  • Total cost of the project can’t be reduced;
  • Each phase of an iteration is rigid and do not overlap each other;
  • Difficult problems delaying may become a thing due to that flexibility that project development allows.

The scope

Applying the model is usually needed:

  • When obvious features and requirements are easily divided into updates plan;
  • When you want to fill the market gap as quickly as possible;
  • When projects require continuous development;
  • With a uniform distribution of properties of varying degrees of importance;
  • When phase-by-phase SDLC is needed due to the early stages of the project;
  • When a project is a low-to-medium risk-related;
  • When the project partly uses a new technology, which has to be incrementally implemented into the old one;
  • When single-pass development is too risky;
  • When you need regular results during all the life cycle.