[AaronBrown]

I disagree with Shandrax, Gonso and iblufftomuch. It's true that you cannot compute expected value precisely, but doing it is still an important discipline. Most bad poker players do things that make no sense given any guess about what might happen. If you make a calculation you are sure you have a plan that works at least under some assumptions. That puts you in at least the middle rank of players.

Also, it allows you to correct mistakes, which is the only way to improve to the top rank. If you put money in the pot expecting 25% folds, and notice that you're getting only 10% folds, you'll get better. If you put money in the pot because it feels like a good time to bluff, how will you know if you are right? Some players react too much to the result of the last hand, others never react even after consistent losses. Math helps you steer a middle course.

I have a different objection, that this calculation has nothing to do with bluffing. If you think about things this way, you should do this with a marginal calling hand, so you still have some chance of winning if called. Bluffs are done with your worst hands.

The main payback for bluffing is that people will notice you do it and therefore call your good hands. Poker theorists differ, traditional ones think you should lose money on bluffs in order to maximize your overall EV. Modern ones, following Sklansky, generally recommend breaking even or better on the bluffs (which means they either bluff less frequently or semi-bluff). But everyone agrees that the main reason to bluff is not this hand but future hands.

That's why it doesn't pay to bluff bad players. They don't notice what you're doing. You can bet with weak hands if they don't call enough, but use your strongest weak hands, not your weakest hands. And there's generally no problem getting bad players to call your good hands, so no reason to risk bluffs.

The good thing about a bluff, done correctly, is you gain whatever happens. If you get called, you more than make up the loss on your next good hands. If you don't, you make money now.