A very good advice. One thing was left out, I think. Implementing the program one self the implementor may: * Gain an insight into the problem he was trying to

A very good advice. One thing was left out, I think. Implementing the program one self the implementor may: * Gain an insight into the problem he was trying to solve he would not have otherwise had * When faced with unexpected complexity, the implementer may choose to solve a less complex version of the problem that may still provide added value, or choose to go some other route entirely. I think this last bit cannot be overstated enough. The easy problems in programming are usually so easy that even novices can solve them in a sensible time, while the hard problems can be hard to get right no matter how many years you have under your belt. Often by changing ones approach the problem can be reformulated into an easier one. If the work is hired, then the consultant may lack the initiative, intuition, courage or experience to go for the possible alternative approach to solve the given problem. Of course, all this depends on the quality of a problem.