The way I look at it is that I want to c-bet FREQUENTLY but not always. "Always is Exploitable" is probably a fundamental rule of poker.

So just find times where it seems a little worse than usualy to bet, and check instead.

one thing not mentioned yet:
you have a modest hand with showdown value (< top pair)

The classic case is holding KK oop on a A-rag-rag board.