To spot the expert, pick the one who predicts the job will take the longest and cost the most. After all is said and done, a hell of a lot more is said than done. Any circuit design must contain at least one part which is obsolete, two parts which are unobtainable and three parts which are still under development. A complex system that works is invariably found to have evolved from a simple system that works. If mathematically you end up with the incorrect answer, try multiplying by the page number.
Computers are unreliable, but humans are even more unreliable.
Any system which depends on human reliability is unreliable. Under the most rigorously controlled conditions of pressure, temperature, volume, humidity, and other variables the organism will do as it damn well pleases. If you can't understand it, it is intuitively obvious. The more cordial the buyer's secretary, the greater the odds that the competition already has the order. Fill what's empty.