Originally Posted by spoonitnow
When you bet $0.80 on the flop and $2 on the turn, this is how BB's stack progresses through the hand:
On the flop, BB has $8.45 behind.
On the turn, BB has $7.65 behind.
On the river, BB has $5.65 behind into a pot of $7.65.
If instead you bet $1 on the flop, the turn pot will be $4.25 and BB would have $7.45 behind. If you bet $2.45 on the turn, the river pot will be $9.15 and Villain will only have $5 behind to push, making the river an easy call against his range.
Another quick consideration for bet-sizing against possible draws: suppose he had a flush draw and the heart hit on the river instead. On the turn he would be calling $2.45 in a pot of $6.70 when he has $5.65 left behind on the river, so he would be getting almost exactly 5:1 implied odds assuming you always called his shove when the river hit the heart. At that point there are 44 cards we haven't seen yet and 9 of those help him, giving him 4.9:1 on his money, making him slightly -EV on his turn call even if you always call the river shove when the heart hits.
If you bet a little more on the flop and keep the same percentage of the pot as a bet on the turn, you can make his situation with a flush draw even worse.
