Software Aging

Software aging, https://www.cs.drexel.edu/~yfcai/CS451/RequiredReadings/SoftwareAging.pdf

Software products exhibit a phenomenon that closely resembles human aging. For a software product, if no one uses it and no machine runs it, it is dead. People do not use a software, may because the software is buggy or the UI is against user's custom.

To reduce the effect of software aging, a software creator have to patch the software to keep it up to date. However, patching processing may also quicken software aging, for adding patches into a software makes it larger and more difficult to be modified. And when no one understands the software implementation and has ability to modify it, the software also dies.

To make a software easy to be modified, it should be designed for change.
To make a software easy to be understand, documentation should be taken seriously.