The cost of maintaining software is rising exponentially and it has been found that software maintenance could account for 70% of the total cost of the software. There are reasons behind this. While more and more software is being developed every day, it becomes hard to maintain them over time.
Lack of proper reporting or documentation and people who work on its development retire or leave without being replaced. Re-engineering the system is not an option because the system that needs to be rebuild could be extensive and not well documented.