TL; DR; and a lot of these concepts are stolen directly from Green Plastic videos and other good posters on these boards (True, Debitel, Orange, Epdaws, others I am shamefully forgetting).
I'd greatly appreciate if we can get some discussion on these topics going. To be honest, I almost think each of these 6 points could deserve its own thread
In SSNL, conventional wisdom is that the pre-flop aggressor should always C-bet in a heads-up pot. There have been a lot of "When should I c-bet?" threads, and I can recall that in many of them, the standard answer was "Heads-up? Always. 3-ways? Sometimes, in position." I was definately one of those posters.
I think there are a couple of reasons this is popular. First, it makes for easy decisions. Raise, C-bet, scoop pot or fold to C/R, move on, until we get to a big hand/big pot situation, in which case decisions are also usually easy. Second, the fact that many C-bets with made hands win the pot convinces many players that their bet was, indeed, the correct move. After all, they won the pot, right? But on this forum, we should by now know that it's rarely that simple. Maybe you could have won a bigger pot. Maybe you just got lucky, and your move that is wrong 90% of the time just won the pot because this is one of those other 10% holdings.
I couple of things have changed my mind about C-betting. Part of it is that, as you rise in stakes, players get a lot more tricky (note that this is a separate attribute than "good": bad players can be tricky, and good players can be tricky). They check-raise more, and with a wider variety of hands. Bad players might check-raise with hands that they really shouldn't check/raise with, like underpairs, or TPNK, or middle pair, and good players will tend to balance it out more by check-raising monsters, semi-bluffs, and big overpairs. But the range of hands players will play aggressively changes as you move up.
I think there are a few factors to think about when you are deciding whether to C-bet your hand in a heads-up pot. To reduce the complexity of the decision trees involved, let's (for the moment) assume 100 BB stacks, and a potsize of approximately 7-10BB.
1) The value of your hand 2) Whether or not you opened in a steal position 3) Whether or not being check-raised will present you with a difficult decision 4) Whether or not betting presents your opponent with an easy decision, or betting will make your opponents turn/river decisions easy 5) Your position 6) Whether or not the pot is re-raised
1) The value of your hand
First, let's consider whether you have a made hand, a draw (weak or strong), or complete air.
Every time you have a made hand, you should be thinking of how to extract the most value from it vs. worse hands. In some cases you may decide that this isn't very feasible (always trying to showdown 22 unimproved on any board is probably not a great idea).
With strong hands, the best way to get value from it is to bet it. AK on an A97 flop, for example. Sets on just about any flop, but especially A-high and drawy flops.
However, there are some strong hands that you should really check (at least some of the time). If you have AK on an A72 rainbow flop, potting the flop is a pretty good way to make just about any one-pair hand without an Ace fold. If you have KK on the same flop (yes, this is a strong hand), you have the same problem. Many times, the best way to get value from these hands is to check the flop, especially if you have position.
With medium strength hands, the best way to get value is never very obvious. For example, 88 on a 459 board with two diamonds. Obviously, there are some worse hands that might call a flop bet (67, any diamond draw), and there are also many turn cards that you will not want to see. But, in genaral, if your opponent folds to this bet, it was almost always a hand that you were a 2 or 3:1 favorite over. An additional problem is that many of those "worse hands" will not just call your flop bet but will raise (see point 3). Whether or not you bet a medium-strength hand should depend on the board texture and your opponent's tendencies with the range of hands that you are ahead of, especially if those tendencies are identical to when he holds hands that you are behind.
There's a very good section on playing draws in Miller and Sklansky's NLHTaP, and I will not repeat all of it, but important points are that the if your draw is not to the nuts, or is very weak, you should be more inclined to bet. With these holdings, the value of winning the pot outright becomes much greater than simply hitting your draw, because if your draw is very weak, you won't hit it very often, and if your draw is not to the nuts, you might lose a lot of money if you hit (or gain very little from worse hands).
Examples of weak non-nut draws that you should be inclined to bet are: bare overcards (these are sometimes the best hand, yes, but if you are called, you are essentially on a 6-out draw), gutshot straight draws (if you can pick up the pot a good percentage of the time, this makes up for winning big pots the rare times you hit, because you just don't hit very often), low flush draws on paired boards (if you hit, you won't get a lot of action except from the nut flush or full houses, unless players are very loose), and open-ended straight draws on two-tone flops (again, if you hit on a flush card, you probably won't get a lot of action).
You would also, of course, be inclined to bet very strong draws, like the nut flush draw with two overcards, or open-ended-straight-flush draws, or pair+flushdraw combos (although if your "pair" is the Ace, then you should be more inclined to check because it is often the best made hand and is not vulnerable to the flush draw for obvious reasons).
With non-nut draws, you should be aware of the possibility of making your opponent sometimes fold a better draw by firing two (or sometimes three!) barrels, which, depending on your opponent, can make you more inclined to bet.
Unless you are giving up on the pot entirely, or have some reason to believe that a delayed bluff will be more successful, I think you should just about always C-bet with complete air -- it's one of the reasons raising a wide variety of hands pre-flop is profitable at all.
2) Did you open in steal position?
Players will give you less credit for a hand. This might mean they are more likely to call you lightly (so you can get more value from moderate-hands) or it may mean that they are more likely to c/r lightly (making it hard to gain value from weak/moderate hands by betting).
Also, your opponents range for calling you preflop is wider when you steal from the CO and Button. Again, depending on how the player plays with his hand range, and his perception of your hand range, should influence your decisions on whether to C-bet, whether you welcome a C/r, etc.
3) How much does getting check-raised suck?
If you have 33 on an A36 board and get check-raised, you are probably doing a little jig in front of your monitor.
If you hold A7 on the same board, that's not so hot. How about KK?
Notice that all those hands have very strong equity vs. the naked flush draw, but the A7 hand and especially the KK hand suck vs. most Aces.
In general, you really don't want to be put in positions where your hand is probably the best hand, but you will have to fold because you might be crushed.
Note that in many cases, the turn action changes things greatly. For one, players very rarely try to c/r twice, and if they do, they generally don't c/r bluff the turn with naked draws (most players would bluff by betting after the turn was checked through). So if it is checked to you on the turn, you can safely value bet, and you can usually fold to a c/r without feeling the least bit bad about it.
If it is bet to you on the turn, your hand is still often best (because your opponent will be bluffing a good % of the time, or "value betting" a weaker hand thanks to the weakness you showed on the flop), but notice how very often your equity vs. most draws has gone way up.
By the way, if you check a hand like KK on the above flop, resist the temptation to slow-play if you hit your 2-outer on the turn. This is because the villain will sometimes be semi-bluffing, and will sometimes be betting an Ace, and he is pretty unlikely to put you on a set given the flop action, and in both cases he will very likely call a big raise.
4) Are you making it easy for Joe Tag or Mac Donkey to play this hand?
Let's go back to the A72 rainbow flop. You're making it pretty easy for both players to play this flop if you pot it. They'll probably just fold anything less than an Ace here. Unless you are holding complete air or a set, this is making things too easy for them, especially if you have position (almost regardless of what made hand you hold).
There are certain made hands (33-55 being the prime examples) that benefit greatly from a flop like this, but other made hands (like 99-KK and weak Aces) that really don't want to make things that easy for Villain, as they are way ahead of villain's non-Ace holdings.
5) Are you in position?
All things considered, in a heads-up pot, I'm much more inclined to bet out of position than in position with my made hands. It's much harder to extract value from medium strength hands (and easier to be bluffed off of them), and the value of simply winning the pot goes way up in comparison to the value of extracting another bet from worse hands.
6) Is this a re-raised pot?
You shouldn't always bet in a re-raised pot. If you have a monster, the pot is big enough to get the money in on 3 streets. And often in re-raised pots, your bets are only going to be called by a very narrow range of hands, which is fine if you hold air, or if you have a set, or AA on 743 flop, but not so hot if you hold KK on a QJx flop, or QQ on an A72 flop.
great post (just skimmed it, tl;dr and all that) but looks like it covers a hell of a lot of important points. I just really hope we can get all the slightly newer players to read this, so we don't have to painfully explain why we actually don't need to know where we stand every [censored] hand!