For example, when we have a pair with a draw, we gain equity against sets by taking away a redraw out, and we gain equity versus other draws with our pair’s showdown value. When we have a backdoor flush draw with Aces, we guarantee a win when we make the flush, prevent our opponent from winning with a dominated backdoor flush, and steal some of his two pair or straight outs.
To help you understand why cumulative equity is important, let’s compare three-betting 10% of our stack with A♣A♠8♥3♦ and A♥A♦J♥T♦. Obviously the latter hand is stronger than those raggedy Aces, and it probably won’t surprise you that the recommendation in QuickPro is not to three-bet a hand like rainbow Aces. For now, let’s assume we did decide to three-bet both hands in this case. The difference between these two hands is a bit subtler than the obvious fact that A♣A♦J♣T♦ flops big more often. It can flop really well in a variety of ways, such as an overpair plus nut flush draw 20% of the time, a nut straight or nut flush around 5% of the time each, and so on. All of this is easy to recognize, but the key is to notice the difference between the two hands on a flop like 9♣7♦2♥.
All things considered, 9♣7♦2♥ is a pretty good flop for Aces, and if we were able to get in 25% of our stack pre-flop, we would contently get the rest of our money in on a flop like this. With only 10% of stacks in pre-flop, getting it in with bare Aces against a normal opponent is a losing play because his stack-off range crushes us.
On the other hand, when we have the JT gut-shot and two backdoor flush-draws, our overall equity is good enough to get it in profitably, which gives us the chance to realize the piece of equity we’re forced to fold when we have bare Aces only. Put simply, our overpair, a gut-shot, and two backdoor flush-draws are each worth something. Individually none is strong enough to play for stacks, but when we have all three, we get to realize each of those smaller, individual pieces of equity. In case you’re wondering, the equity added by one backdoor flush draw in a standard hand vs hand match-up is between 1-3%, depending on what the actual holdings are.