The Software Development life-cycle does not cease after releasing a functional product. Truth be told, software continues to evolve as long as it is being used and not labeled as condemned. This evolution is necessary for accommodating changes triggered by new requirements of the system and its users. Software maintenance is commonly associated with bug fixing, but in reality there is much more to it. People also assume that software cannot deteriorate because it is virtual and immune to wear & tear; as long as the hardware around it is fine, there shouldn’t be a problem.

Software maintenance is a process that begins in the production stage and may remain active for decades. It follows the operations phase and is extremely important for ensuring that the performance & productivity of your software is not compromised. Software maintenance is an umbrella term that can be divided into 4 categories:

• Corrective maintenance
• Adaptive maintenance
• Perfective maintenance
• Preventive maintenance

Corrective maintenance

Corrective maintenance usually refers to software change implemented in response to bug reports submitted by users. This could be some acute issue that is causing the software to act against how it normally should. It is possible that the occurrence of the issue is not evident on the user interface, but users suspect its emergence any time. Corrective actions cover address errors, or any other software deficiencies affecting the code, design or logic. Any amendments made before a user has noticed or complained, are not apart of this category.

Corrective changes account for about 20% of the total maintenance work on average. If you spend too much time on corrective maintenance and the work put into it exceeds the standard value noticeably, that is definitely alarming. This is an indication towards one or more deep rooted problems within your development system. Perhaps your testing practices are poor, your code is low quality or the team lacks competent developing skills.  

Adaptive maintenance

The need for adaptive maintenance emerges when there are changes within an environment where your software runs. Adaptive changes are generally made in advance, i.e before your audience may encounter the potential issues. A classic example is running your application in a new version of a browser. Although the new version isn’t public yet, the beta version is available. Therefore, you make changes to your app to make it compatible with the beta browser.

When the actual version comes out, users will not face the expected problems because you fixed them beforehand. However, if you wait for the public version and make changes after the audience has encountered errors, those late changes will be classified as corrective maintenance. Actions like updating an operating system, hardware, server, system policies, etc. are frequent reasons for exercising adaptive maintenance. Adaptive changes account for 20-25% of maintenance work carried out in IT development organizations.

Perfective maintenance

Perfective maintenance is related to changes made in order to improve or enhance your software application. They are not changes devised to eliminate any bugs or errors, but simply to add new features. Nonetheless, user requests and requirements are largely responsible for making these kind of changes. Assume that everything within your software system is perfectly working, but you want to add or remove functionalities to make it better.

Companies tend to alter their software system with regard to technology advancements or competitive products in the market. Realistically speaking, perfective changes cover the major fraction of maintenance work, which is 50-55% on average. This is no surprise because software is constantly subject to upgradation in order to survive the rapidly changing trends in technology.

Preventive maintenance

Preventative maintenance refers to changes made for increasing the durability and reliability of your application. The objective is to make your software easy to maintain and be less susceptible to any factor that is capable of causing degradation. It is relatable to adaptive maintenance as it involves forecast of potential risks of the future. They disparity is that adaptive changes are made in accordance to issues that are guaranteed to propagate, whereas preventative changes are not based on any actual threats; they are solely the outcome of hypothetical concerns.

Important Aspects of Software Maintenance

It’s already crystal clear how fundamental Software Maintenance is to the success of your software application. What you probably haven’t considered are the wonderful insights you can discover if you monitor and evaluate the changes you implement. Make sure to always recognize and record the type of maintenance changes you make along the software development cycle. There are no predefined rules and limits to the procedures, but the time and resources spent on them can say a lot about the status of your company. Some maintenance projects can fall into multiple categories, so don’t let that get you anxious.

No code is perfect and that’s why a handful of bugs will always show up once your software is put through testing. As anticipated, your team will be executing vigorous corrective changes soon after release. Many errors are only identifiable in the production stage, so high levels of corrective maintenance at this stage is typical. On contrast if corrective changes are on-going long after the launch of an app and adding up from day to day – that’s just not right. Corrective costs are fairly high, so too much of these could be immersing you into financial debt. It’s better to invest in adaptive changes if possible, because they will not cost as much.

You cannot turn a blind eye to maintenance requirements, unless you wish to see your software crumble to ash. Software systems age and become nonfunctional if not updated or taken care of on a regular basis. If the system is constantly growing or expanding its user base, it will obviously require greater amounts of maintenance too. Software teams that keep on adding new features to their software are likely to remain busy with corrective changes consequently.

Sooner or later they will get to a point where 100% of their time goes into corrective maintenance work. This is not an ideal place to be in because it symbolizes zero growth. As all the time is used up maintaining previous features, the odds of making further additions are non-existent. Preventative maintenance is more like a game of chance; it can be highly beneficial or excessively worthless. As the measures taken completely depend on intuition, it’s difficult to guess the fallout.