You are right Billy, but believe me when I say that there are so many "smoke sellers" (an Italian way of saying) out there that it is not easy to find a good "car".
Darvas himself in his book speaks of his own sad experience when relying on other people's expertise: there were no robots at that time, but there sure were as many smoke sellers as there are today, and most probably today they are even more.
To make one's own experience in the field, at least, can help separating the good guys from the bad.