There are primarily three reasons to bet in No limit holdem. The first and most important is betting for value. Especially at the lower levels this is where 95 percent of the money is won or lost. Secondly, we can bet to bluff someone off of a better hand. Lastly we can bet for protection.
Betting to protect your equity in the pot is a much more common concept in PLO when equities run much closer even with one card to come. The concept still exists in holdem but it is usually misunderstood.
At the lower levels you will see players commonly bet big with what they think is the best hand to “protect” against the draws. What they do not understand is that they want to in fact get value from a draw. Say for example we raise to $35 in a $5-$10 no limit game with A♦ K♦. Only the big blind calls. The flop comes out 9♠ K♣ 3♠. The big blind checks and we bet $85. Our opponent hems and haws and finally folds 6♠ 7♠ face up saying “that’s too much to call on a flush draw.” We happily take down the pot not realizing that we have made a critical mistake. We actually WANT the draw to call so long as we do not incorrectly pay off on future streets.
It is pretty rare that we actually want to bet to protect our hand in no limit holdem. The situations are a lot more uncommon than people think. Usually we want to bet to protect when we have an unpaired ace high hand that we think is best and do not want to give off a free card to another unpaired hand that would not call a bet. Say for example we hold AJ on a 9337 board. We were the preflop raiser and we checked back the flop. Now our opponent has checked again on the turn and we are fairly certain that he does not have a pair. It would be bad for us to wrap behind again and have a hand like KT, which would fold right now, to catch up to a better hand.
Another example of hand protection is when we think that our opponent is semi bluffing the turn but, if he misses, will not bluff the river and the pot is rather large. Take a board of 8♥ 3♦ 7♦ 2♥. We hold KK and have now been check raised on the turn. Let’s say we only have a pot sized bet left after we call the check raise. If we think that we have the best hand (which may not always be the case) we should probably just ship all-in especially if a hand like 45 will not bluff the river if missed. We are actually giving our opponent a free shot at our stack by not moving over the top of his check raise.
Lastly, and probably the most misunderstood protection bet occurs when we hold a near nut hand that will only get action on a future street if we are beat. This commonly occurs when we flop trips with a very good kicker. Say for example we raise with A♥ K♥ on the button. The small blind calls and a limper calls. The flop comes out K♣ K♦ 8♠. It gets checked to us and we decide to slow play since there are no draws on the flop. The turn comes the 2♦ and the small blind now leads out. The limper folds and we decide to raise. The small blind now reraises and we snap ship all-in. Our opponent beats us into the pot and much to our dismay tables 22.
This scenario is less common at the higher levels nowadays but years ago when a lot of people played no limit poorly I used to see it all the time. They thought that their hand was so big on the flop that they didn’t need to bet and did not realize that they in fact had to protect against these type of two out hands that would only give them action on future streets if they had them beat.