Troutman's Laws of Computer Programming

• Any running program is obsolete.
• Any planned program costs more and takes longer.
• Any useful program will have to be changed.
• Any useless program will have to be documented.
• The size of a program expands to fill all available memory.
• The value of a program is inversely proportional to the weight of output
• The complexity of a program grows until it exceeds the capability of the maintainers.
• Information necessitating a change in design is always conveyed to the implementors after the code is written. Corollary: Given a simple choice between one obviously right way and one obviously wrong way, it is often wiser to choose the wrong way, so as to expedite subsequent revision.
• The more innocuous a modification appears, the more code it will require rewriting.
• If a test installation functions perfectly, all subsequent systems will malfunction.
• Not until a program has been in production for at least six months will the most harmful error be discovered.
• Interchangeable modules won't.
• Any system that relies on computer reliability is unreliable.
• Any system that relies on human reliability is unreliable.
• Investment in reliability increases until it exceeds the probable cost of errors, or until someone insists on getting some useful work done.
• Adding manpower to a late software project makes it later.
• There's always one more bug.