What is software maintenance
Software maintenance is the modification of a software product after delivery to correct faults, to improve performance or other attributes, or to adapt the software product to a modified environment.
A common perception of maintenance is that it merely involves fixing defects. However, one study indicated that over 80% of maintenance effort is used for non-corrective actions. This perception is perpetuated by users submitting problem reports that in reality are functionality enhancements to the system.