2. Need for maintenance

Nearly all systems will need maintenance over their lifetime. This is because

• Something in the system needs fixing (corrective maintenance)
• External changes forces a change to the system (adaptive maintenance)
• Something can be improved. (perfective maintenance)

In terms of the Systems Life Cycle approach this is the 'maintenance' phase of the system.

There are many reasons for maintaining a system that fall into the categories given above

• An error / bug is serious enough to need fixing
• A new business process needs to be incorporated.
• A security vulnerability in the system has been found and needs patching
• An user has identified how the system could be improved
• The hardware or network is being improved and so the system should take advantage of that.