"Portions of code have to be changed while other portions are written. They often lead to redundant code or uninitialized variables, partially covered conditions, and wrong return results. Code gets a "do not touch" reputation because changing anything renders the whole project unstable. Often the code works, but the project is more a failure than a success because it cannot be extended or re-used.
"Another reason for planning is the ease of bug fixing and the costs associated with it. Open source developers often do not think about it until they start selling their services or work to commercial companies."
