I agree with Jeff, and here's an anecdote about "DON'T underexpose and DON'T overdevelop". My apologies if it is drifting somewhat from the topic.(posted 9396 days ago)When I was even younger than I am now, I used to believe that I could increase the effective speed of my film by stewing it for a long time in developer. What I didn't fully appreciate was that the major effect was to increase contrast. This raised the density of mid-tones appreciably, and I used to judge "correct" exposure as that which reproduced a grey card as grey on the negative. For some styles of photograhy, this is not a terribly bad definition of EI (Effective Index), although it is not the standard definition. However, I now normally judge "correct" exposure (and development) to be that which gives me good detail in whatever shadows I am interested.
Incidentally, the (dubious) definition of correct EI being defined as reproducing a grey card as mid-grey on the negative seems to be adopted by some manufacturers. Watch out for phrases like "you can expose at EI 3200 if you don't care what happens to the shadows".