Game theory describes a method of play that puts your opponent into a "damned if he does; damned if he doesn't position" where he can't win despite what he does. If he's getting 3 : 1 odds
from the pot, then your ideal bluffing frequency is 25%.. That way, he breaks even at best.
Of course, it's not always so cut and dried simply because you don't know the exact odds for every situation. Sometimes, there are better ways to exploit opponents: bluff nits more often, and call compulsive bluffers more frequently, than game theory would suggest.