“Photography is a lot like cooking!
I have encountered a lot of folks who worry about getting development times just right, or they are concerned about what f-stop they should use, or what is the right amount of sharpness in a digital image, and on and on.
The real deal is that the only thing that is really absolute in photography is film speed. Everything else is like cooking. What is not enough or too much is a matter of personal taste. There is no right or wrong.
It takes a finite and specific amount of light to rattle the molecules in film or sensor. For shadow detail, if an exposure falls short of that specific amount for an important shadow, there is nothing there to develop: nada=clear film or sensors that were never rattled. On the highlight end, film has an extreme range, but at this writing, a single exposure digital image is just as limited on the high end. Too much exposure over-saturates the sensors so that there is no tonal recovery possible.
So the mantra is:
IF you want certain shadow detail, you MUST give enough exposure!
IF you do not want your highlight blown out with digital or transparency, you must NOT over-expose!”