when to go all in, vs. a pot sized bet?

[morgant]

I often hear the ringers around here stating bets in terms of the percentage of your stack size. can someone elaborate on these percentages. like if a pot sized bet is X% of your stack you should just push all-in, etc....
thks
morg.

[Kurn, son of Mogh]

The general rule of thumb is 33-40%.

The logic is, If you bet 1/3 of your chips and are called, the pot is now roughly equal to your remaining stack, making your post-flop decision to bet all of your remaining chips or fold. If you think you have the edge preflop, why not put your opponent on a tough decision then?

By betting too high a percentage of your chips, you've already put yourself in the position of having to make a decision that could lose all your chips without putting that same pressure on your opponent.

[gunboat]

There is one exception to all-in I use when I need to commit more than 1/3 of my stack.

If I am closing the action in EP (e.g. in the BB) and I am sure my all-in will be called. I will call, then bet all-in on the flop regardless of what it is. This will sometimes fold a better hand that didn't hit and gives me one additional chance to win the pot.