From what I gather, with the little research that I have done, is that it really is only on the areas that are exposed to alot of sun over time. They literally are an accumulation of errors. The more sun (UV) over time, the higher the risk.
As mentioned above the most common areas are the face, hands, neck and arms. The only good thing I guess (best of the worst) is that BCC's don't have the habit of spreading to other areas of the body (less than 0.1%) unlike the dreaded Melonoma's. Theoretically you could let one get relatively big and still be able to chop it out and thats that. BUT....... if they do grow into bone or blood vessels then there is a chance that it can be fatal. The idea, of course, is to catch them early.
One other thing I found out, for all you guys like me that have had one cut out, there is a 32% to 51% chance of getting another one within 5 years..............Now thats a crap thought.
Cheers