Actually, I have several leaks, but I have one that I recently discovered.
Here it is: I never suffer bad beats.
Seriously, and I should be concerned.
Let's do a little math to prove a point we already know. Say you have a made hand on the turn and your opponent is drawing to beat you. There is $200 in the pot. Let's say he has an 18% chance, which is about an average amount for the various things to which he could be drawing.
If you bet precisely $56.24 then he is getting exactly the 4.56:1 odds he needs to call. To bet anything less than that would be giving money away. If fact, from an EV perspective, you give away $36 in equity by checking instead of betting.
If there is a 100% chance that your opponent will fold to any bet of $56.25 or more, then there is absolutely no difference between the EV of betting $56.24 or betting anything more than that. Of course, there is never a 100% chance of your opponent playing perfect poker. So, you should try to figure out what is the highest bet > $56.24 that will still get a call. I bet that if you throw $75 into a $200 pot, you will get a call from a drawing hand quit a bit more often than not. A $75 bet gives you $12 more equity than a bet of $56.24 does. Each incremental dollar bet both increases your EV if called and decreases the chance of getting a call.
Of course, getting called means that you will lose sometimes (bad beat). But when you win, you will win enough to more than compensate for that. I have been letting my fear of the bad beat keep me from betting optimally.
So here is my problem: I'll bet something like $150 in that situation. I almost never get a call because few donkeys are so donkelicous that they would call for those odds. So, I get to feel good about myself for winning the pot, but I should be criticizing myself for not trying to win more money. It's one of those leaks that hard to spot because it doesn't involve losing a pot. It is just an opportunity cost of not winning a big enough pot.
I'll pause right here and admit that we are only talking about pot odds and not implied odds, which are more relevant. Implied odds require a lot more math and words to work through, and they wouldn't change the gist of this post, which is that you should try to get the biggest possible call you can get that is -EV for your opponent.
A simple formula helps determine what the right amount to bet is. Figure out the pot odds your opponent needs to call...let's say it is 4:1. Subtract 1 off that first number and get 3. Divide the pot by 3, and you have your magic number. Then just bet an amount that is a bit higher than that. Using our example from before, we'd take 4.56:1 and subtract 1 to get 3.56. The $200 pot divided by 3.56 gets that magic number of $56.24. Now that we have our magic number, we can comfortably bet an amount that is a little more, say $75. Doing this math will make sure you don't accidentallyunderbet. It should help you to not overbet, either, as you know the target from which you shouldn't stray too far. Betting $150 is so far above $56.24 that I should realize that I am needing to slow down a bit. Of course, the other (circumstantial) evidence that you need to bet less is if you never suffer a bad beat.