Quick changes in the modern technical world make developers keep up while they are still delivering top-notch software on time. To streamline the development process companies use different approaches. Here different software development life cycle models are used.

All software development methodologies can be adaptive or predictive. The adaptive subcategory includes Agile SDLC, while Waterfall, V-shaped, Iterative and Spiral models all belong to the predictive approach. They are designed to meet a number of development requirements and expectations that differ from company to company.

Here you will read about the predictive software development models:

V-shaped SDLC Model is based on the Waterfall model. The development process is associated with flowing water. The development team moves step by step through different SDLC stages. Every stage finishes with testing and a team moves on to the next only after the previous stage is complete. This model is also named Validation-Verification. If all requirements have been fulfilled and the team can move on to another software development phase. Don't forget that you cannot easily move back a step to fix or add something if you use the V-shaped SDLC model. This model won’t work for you if your software product is new, has many features to be implemented, or you are not sure about the final functionality.

The Iterative approach can be used in projects without the full list of requirements, you only need the requirements for the functional part. Later in the development process, these requirements can be expanded. The approach goes through all SDLC steps, from analysis, to design, to coding, to testing, and back to analysis. The process is repetitive and lets create a new product version for every cycle. Each iteration lasts from two to six weeks. The result in mind is the release of a new component, which is then added to the existing components and features. The software development team moves the project to the final version of the planned software step by step. The need for repetitive iterations is considered to be the main flaw of this model. If it is not used wisely it may quickly drain the resources for unnecessary changes. This approach will not be good for startups with limited financial means.

In Spiral SDLC Model a great emphasis is placed on risk analysis. The whole development process is split up into many small phases to follow. It may lead to the loss of time and money if the product is new and the final product does not need to be excessively documented. This model can be very expensive for small and low-risk projects.

###Waterfall vs Agile SDLC: Why Companies Choose the Agile Approach

Waterfall model is regarded to be the oldest among SDLC models. It underlies several other software development approaches, like the V-shaped and Spiral models. It was developed by Winston W. Royce in 1970. He wanted to convert a risky development process into a linear process that would lead to the desired software product.

This model uses a linear approach, which means that you need to finish one phase before moving to another one. Each stage depends on the previous one and there is no going back.

The main disadvantage of this model is its inflexibility. Projects which use SDLC model are easy to manage, but as soon as a stage is finished there is little or no room for revisions, so fixing any problem is challenging.

These models have pluses and minuses which should be considered. They can be utilized for small and big projects. Although, the Waterfall model has some challenges for changes to the project in later development phases. On the other hand, the Agile SDLC model is flexible and changes can be made at any stage of the development process.

Here is a comparison table for Agile SDLC and traditional SDLCs.

So, the most important advantage of Agile software development life cycle implementation is plain to see. The Agile approach covers the continuous changes that dominate in software development processes. That is why teams can deliver working software fast and release updates more often. So, not to adopt Agile SDLC seems not reasonable.

Here https://mlsdev.com/blog/agile-sdlc you can get full information about the Agile SDLC model, its correlation with traditional SDLC models, and how to make use of the best Agile practices.