[phydaux]

Read Professional No Limit. The middle third is all about this.

Cliff notes:

1/3 of your stack is the commitment point. Once 1/3 of your starting stack is in the pot, and there are still cards to come, it is usually wrong, mathmaticaly, to fold your hand unless you are sure you're beat. If you are not sure you are beat, then you are only rarely more than a 2:1 dog to win the hand. And that's what the pot is offering you, plus implied odds.

So once 1/3 of your starting stack is in the pot, your two best options are to either fold right away or be willing to get all in.

10% is the commitment threshhold. Once 10% of your starting stack is in the pot, then one reasonable-size bet (roughly pot-size) will bring you to the 1/3 mark - the commitment point.

So once 10% of your starting stack is in the pot, you need to start making a plan - Am I probably going to fold this hand, am I going to bluff at the pot (thereby putting ~1/3 of your stack in the pot) and fold if I'm played back at, or am I willing to get all in?

(BTW, "willing" doesn't nessasarily mean "intending." A lot of players get tripped up there.)

The moral of the story is that, because of the exponential growth of NL hold'em bet sizes, commitment comes much earlier than most players realise. So you need to start planning your hand around commitment very early.