What are the different types of SDLC? Which one is the best?

Among  the basic concepts of a software life cycle is a model. An SDLC model works as the foundation of development  and should be adjusted to its team, plan, and requirements of the product. There are various SDLC models, and each one of them has its own pros and cons. Today in this guide we will be talking about the ten main types of SDLC models, their specifications, pros, and cons.

SDLC: Overview

The procedure of planning, creating, testing, and launching software is known as SDLC or Software Development Life Cycle. Actually, it is a plan that contains different phases. Firstly, let’s have a brief look at the most important phases of SDLC. 

• Consulting.
• Planning.
• Designing.
• Architecture.
• Coding. 
• Implementing.
• Testing.
• Launching.

Pros of SDLC:

• The review is formed at the end of every stage which lets maximum management control.
• SDLC approach allows developers to make a considerable system document that makes sure that the requirements of the software are meeting the mentioned objectives and business goals.
• Many products can be made this way according to the requirements and standards defined by the user. Developers can later improve these products to make sure they are meeting the requirements of the business.

Cons of SDLC: 

• Creating documentation is expensive and consumes a lot of time. It’s even a harder task to keep the documentation updated.
• SDLC promotes stiff execution instead of being creative.
• Users might not be able to review and evaluate the products conveniently according to the requirements of their business.

Types of Software Development Life Cycle Models

There are 10 total types of SDLC Models. They are as following:

1- Waterfall

2- Agile 

3- Spiral 

4- Big Bang 

5- Iterative 

6- V-shaped 

7- Rapid Application Development 

8- Evolutionary Prototype 

9- Capability Maturity 

10- DevOps 

If you want to get a detailed look at these types of SDLC models, continue reading this article. 

1- Waterfall model

The waterfall model is an old model used to create a system with a sequential and linear approach. It is known as the waterfall method as it develops from one system to another in a downward method. It is the easiest and the earliest model of all the SDLC methods. In this model, the complete process of establishing software is divided into cycles, and each cycle starts only when the last cycle ends. Every stage comes with its separate plan of the project and depends on the preceding stage’s data. The major phases of SDLC of this methodology are gathering, deploying, and launching. The waterfall model is used in SDLC as it can easily be planned and run. The procedure is rigidly recorded, and every stage’s procedures and results are user–specified.

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When should you use the waterfall model?

Every project is separate, and this SDLC model needs to be in touch with a lot of internal and external requirements. The waterfall method is perfect to use when:

• The requirements of the project are understandable and in detail.
• The product is defined stably.
• The tech stack is not dynamic and defined already.
• The resources are available with the required expertise.
• The procedure is quick and convenient. 

Advantages of the waterfall model:

• The procedures in this model are done on an individual basis, and there is no overlapping.
• The main points are defined easily.
• Setting the priorities of a task is convenient.
• The revenue and time of this development method are easy to plan.
• It works perfectly for short arrangements where the necessary requirements are clear.

Disadvantages of the waterfall model:

• It won’t be suitable for long, complicated, and object-oriented projects.
• You get the required product at the very end of the process.
• The team won’t be able to know beforehand the possible issues that may occur.
• The evolution of each stage cannot be calculated easily.
• It doesn’t work for plans that have customizable requirements.
• It has a high uncertainty amount and is at high risk.
• Modifying the scope while the cycle is going on may lead to issues.

2- Agile Model

An Agile model is a kind of project management procedure, where demands and solutions are evolved with the help of collaborative effort of self-organisation and cross-functional teams and users. This model of SDLC is thought to be very practical. It separates the development process into short cycles with time boundaries, which lets the product delivery be quick. After every cycle ends, the software is then examined. This SDLC model is the commonly used model as a replacement to the waterfall model. As this model has cycles, it improves the interaction between the team. It mostly depends on the interaction between the user and the development project company. The agile model is about being adaptive without the need for a lot of planning. The software developers adapt the process according to the requirements of the products changing.

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When to use the Agile model?

This model is getting famous nowadays as it is adjustable and adaptable. It can be used when:

• The changes should be applied.
• The conditions of the project are not well thought out.
• Increased attention is needed to manage risks.
• The whole project is free in terms of actions and time.

Advantages of the Agile model

• Going back to the prior cycles needs little money and time.
• Allows the development team to be more flexible.
• The repetitions are clear and short.
• The threats are less as the project is flexible. 
• The first operating version of the product is released fast.
• Minimal resource needs.
• Improves teamwork.

Disadvantages of the Agile model

• The cost of the concluding
• Outcome is hard to be calculated.
• Updated changes might not be able to connect with the architecture developed previously.
• The developers need to be customer-oriented and expert in this field.
• The final outcome may be sent to the customer later than the deadline schedule.
• It relies highly on the clientele who can turn this project into a bad one.

3- Spiral model

In the spiral methodology, the software development cycle is separated into monotonous configuration and mocked up phases. The main problem of this SDLC model is to find the correct moment to continue with the next stage. Each stage encircles  such aspects as planning, analysis of risk, engineering, testing, and evaluating. These stages are done a few times until we get the final product. Currently, it is one of the most modifiable models as it gives developers some liberty to create a customised product. They can just shift to the next phase even if the work on the precedent stage is not finished yet.

When to use the spiral model?

This methodology is famous for software development as it has a high-risk reduction rate, and here are the cases when the spiral model is most suitable for usage:

• The revenue is less, and risk estimation is notable.
• The customer doesn’t know about the requirements of the project.
• The project has a high danger  level.
• The determined requirements of the project are complex.
• The project is long-lasting according to the chances of interchanges.
• Customer response is important, especially for brand new product lines.
• The needs of the user are not known.  

Advantages of the Spiral model

• Flexibility to changing conditions.
• Allows wide use of mock ups.
• The scheme is sent to the customers before the deadline.
• The hazardous parts of the software development life cycle can be done more closely.

Disadvantages of the Spiral Model

• It could be a little expensive for low-risk or small projects as it has a change implementation.
• The Spiral may be continued for an unknown time period.
• The end of the project is complex to predict.
• A lot of small phases might need comprehensive documentation support.

4- Big Bang model 

This model is really different from all the software development models. Its key point is that there is no specific process a developer has to follow. There is only one stage in this model, which is “bang,” which means to start the project right away. Even the requirements of the customers are not defined clearly in this model. As a rule, there are only one or two engineers working on this plan. It may seem weird, but it is perfect for modest projects by saving energy, cost, and time on the starting phases.

When to use the Big Bang Model?

This model is really flexible and allows the developers to start operating on a development project immediately. The use of the big bang model will be the most suitable when:

• The project is non-theoretical and modest.
• The development team contains 1-2  people only.
• There is no deadline given by the user.

 Advantages of the Big Bang Model

• It doesn’t need any pre-planning.
• It only requires a few resources.
• It is easy and modifiable for programmers.
• It aims to deliver the product quickly.

 Disadvantages of the Big Bang Model

• It is too effortless for hard projects.
• It has a high risk of misunderstanding.
• It can get very costly if the conditions of the project are unclear.
• The project might even need to be done again from the start if there is any misunderstanding.

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5- Iterative Model

The Iterative model is just repetition in a bodied form. Instead of starting a project with clearly defined requirements, you apply a few software requirements, then test, estimate, and point out more requirements. A new version of the software is developed at every stage or repetition. Just keep repeating until your complete system is ready.

One vital point this model has over other SDLC models is that it provides you with a working version of the product even at the initial stages of the process and makes it economical to make any required changes. One of its cons is that the resources can be eaten up quickly if you repeat the process over and over again.

When to use the Iterative Model?

This model is repetitive and is only suitable for cases like:

• When the customer requirements are clear and easily understandable.
• When the required software is large.
• When there is a need for changes to be implemented in the future.

Advantages of Iterative Model:

• Possible issues are known and dealt with at the initial stages of the project.
• Useful prototypes are developed at the start of this project’s life cycle.
• The documenting of this project requires less time, while more time can be spent on designing.
• The progress can easily be calculated.
• Changes to this project are not that costly and can be implemented conveniently.
• Testing can be done by modules being small.
• Most of the risks can be known during the repetition, and higher risks can be dealt with first.
• Successive repetitions can be conveniently managed as milestones.
• A working product is submitted with every repetition.
• Operating time can be lessened.
• Customer feedback depends on the working product and not its technical specifications.

Disadvantages of Iterative Model:

• In this model, more resources might be needed.
• Each phase that is successful is rigid with no overlapping.
• More intensive project management might be needed.
• It might be hard to point out a closing date for this project to end.
• Highly expert developers are needed for the analysis of risk.

6- V-shaped model

The V-shaped Software development model is a kind of waterfall model. In this model, the verification and validation stages are done parallelly. The testing phases correspond to some development phases. This model comes with a strict plan, and just like the waterfall methodology, the next phase won’t start until you’re done with the previous one. According to this model, the testing should be done hierarchically, and each stage comes with a deliverable. Errors in this model can be detected easily at the initial stages.

When to use a V-shaped model?

This model highlights the testing activities and increases the chance of high-quality and error-free product delivery. V-shaped models are suitable when:

• The project is small, and the requirements of the customer are understandable.
• The team of developers consists of qualified engineers, especially testers.
• The project needs thorough testing.
• Proper technical resources are accessible. 

Advantages of V-shaped model

• Every stage has a definite end result, so it is convenient to run.
• Every phase is completed one by one.
• Testing is done at the initial stages.
• It is clear and convenient to use.
• The project management and tracking results are effortless.

Disadvantages of V-shaped model

• This model is not flexible.
• It has a high-risk rate.
• The phase repetition cannot be done.
• The handling of coinciding events is hard.

7- Rapid Application Development Model

The term RAD is short for Rapid Application Development. As the name tells, the RAD model is a way of developing a high quality product quickly by:

• Requirements through focus groups or workshops.
• Prototyping and pretesting of all the designs by customers.
• Re-use of some components of softwares.
• A strict schedule which postpones any improvements of design to the next version of the product.
• Less formality in the communication of team and reviews.

When should you use the RAD model?

The RAD Methodology can be used only when:

• A system should be created in around 2-3 months.
• The requirements are clear and understandable.
• The customer is included throughout the process of production.
• There is less technical risk.
• There is a need to make a system that can be modularized in a time span of 2-3 months only.
• The budget of the customer is high so they can afford to hire software designers for modelling as well as the cost of tools for coding.

Advantages of the RAD Model

• It is adjustable according to required changes.
• It is great when you have to lessen the risk of the overall project.
• It is more convenient to send the deliverables as high-level codes and abstractions are utilised.
• Because of the code reuse and code generators, there is less manual coding.
• Due to prototyping, there is a possibility of less defects.
• Every cycle in RAD delivers the best functionality to the customer.
• With less developers, productivity can be more even in a little time.

Disadvantages of the RAD Model

• Not all softwares are compatible with RAD.
• It is not suitable if there is high technical risk.
• If developers are not committed to making the software timely, RAD projects can be a huge fail.
• The product will have less features as the time will be less so the features can be pushed to the later version to finish the release in the short time period. 
• Less scalability will occur as the application developed by RAD starts as a prototype and turns into the final product.
• Progress and issues cannot be tracked easily as there is no documentation to show what has been done.
• It needs highly expert developers or designers.

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8- Evolutionary Prototype Model

In this SDLC model, the prototype first developed is fixed according to the customer feedback until it finally gets approved. As compared to Rapid Throwaway Prototyping, this model has a better approach as it saves a lot of time and effort. As developing a prototyping from the start for every repetition of the process can be really hard for developers, this method makes the process convenient.

When to use the Evolutionary Prototype model?

The evolutionary prototyping model can be used only:

• When the requirements are not clearly understood at the initial stage.
• When the requirements are changing quickly.
• To develop user interfaces
• To develop technology software-intensive systems
• To demonstrate technical feasibility of the required product. 

Advantages of the Evolutionary Prototype Model

•  The customers can check the partial product at the start of the cycle. This makes sure the customer is completely satisfied with the final product.
• New requirements can be adjusted as there is an option of fixing the product.
• The developers can conveniently figure out any missing functionality.
• Developers can easily detect any error at the initial stage of the process which saves time, effort, and cost, and increases the quality of the product as well.
• The prototype that has been developed can later be used by the developer again for difficult projects in the future.
• The designs are flexible.

Disadvantages of the Evolutionary Prototype Model

• Looking at the time it consumes and money it requires, it might be a little costly for medium sized projects.
• There might be too much fixing and changing in requirements each time the product is checked by the customer.
• Poor documentation if the customer changes the requirements continuously.
• It is hard for developers to adjust all the changes requested by the customer.
• There is no fixed number of changes that would be needed until the product is finalised by the customer.
• Developers who hurry in building prototypes can end up having sub-optimal solutions.
• The customer might not be interested in the final product if they don’t like the initial prototype.

9- Capability Maturity Model

The CMM is a standard process for measuring and analysing the maturity of the development process being done in an organisation. It is a model used to develop and adjust a development process of a company.

This model can be used to evaluate an organisation against a scale of five process maturity levels depending on the key process areas. It tells the maturity level of an organisation depending on the project the company is working on with the customers.

The five various levels of the CMM are:

• Initial
• Repeatable
• Defined
• Managed
• Optimising

When to use the Capability Maturity model?

CMMI can be used:

• To guide process improvement across a project
• To guide process improvement across a division
• To guide process improvement across a whole organisation.

Advantages of the Capability Maturity Model

• It enhances the capability of an organisation by increasing the ability of their workforce.
• It makes sure that the development ability is a feature of the whole organisation and not just a few people.
• It aligns the motivation of all the people working with that organisation.
• This method is economical and short.
• Only a little time for preparation is needed.
• Improvement proposal to get executive support.
• It detects the problems to extract the most vital tasks to do. Every action is given a specific task.

Disadvantages of the Capability Maturity Model

• Low confidence level in the results. The method depends on the people who fill out a questionnaire very knowledgeable on the model. The results should be verified by a group of experts who have every required information on the organisation’s process.
• It is not useful for an independent review of the abilities of an organisation.
• High costs if the company is new.
• No resources are given for a full-time coordinator.
• Difficulty of applying the change against the tight working capital levels.

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10- DevOps Model

The DevOps model is one of the latest models in the process of SDLC. As its name recommends, developers and operations teams work together as a single team. This helps increase innovation and position a better quality and reliable software product and its functionalities. In this model, short and frequent updates are given for the products. Discipline, constant feedback, improvement of the process, and automation of manual processes of development are all signs of a DevOps model.

When to use the DevOps model?

The DevOps practice, process, and workflow is based on the philosophy of the DevOps. It is used to build security into your SDLC at scale and speed without sacrificing on the quality and safety while reducing the risks, the friction and costs, and ensuring compliance.

Advantages of the DevOps Model

• Quicker product release and more time to market.
• High productivity and efficient process.
• Reduced production cycle.
• More operational support.
• Motivated and engaged workers.
• Better management of customer experience.
• Clear vision of product for the working team.
• Enhanced product quality and success rate.
• Improved support and flexibility in the development.
• Less chance of product failure and more chance of self-improvement.

Disadvantages of the DevOps Model

• It needs proper mindset throughout the company.
• Less business security by outsourcing the operations of the DevOps.
• Handling the Legacy system is complicated.
• Practising security is hard too.
• Hiring the right people who are DevOps experts is hard.
• Hard to choose the number of tools and switching them.

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How to choose the correct life cycle model for your software development project?

Now that you know about the most important kinds of SDLC models, let’s talk about picking the right model for your software development project. Here are the basic things to consider before choosing one for yourself.

• Size of your time and their expertise.
• Required Technology.
• Location of your team.
• Type and size of the project.

Which SDLC model is right for you?

Each one of these SDLC models has its own process for different kinds of project challenges you will face in your career.

Finding the correct SDLC model for yourself depends on not just the outcome you expect but the boundaries by which your project is carried out. You also need to choose a software development environment as it is helpful in automating the routines of SDLC.

Conclusion

During the growth of SDLC, various models emerged from the basic waterfall model to meet different needs and expectations of a project. There is no model that can work perfectly for all your SDLC projects, conditions, and budget. 

Every model has its own features that make sure the development process works smoothly and is successful. We hope this article was helpful for you in getting to know more about all the kinds of SDLC models available. If you’re looking for a software development agency, you can Contact us.

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