[RustyBrooks]

You consider pot odds for 1 card to come when you are considering the current pot size against the current bet.

You consider pot odds for all the remaining cards when you are considering the current pot size against the current bet plus all the likely action before you get to the end. For example if your opponent bets on the flop and you expect him to bet the turn also, then you are getting P+2:2 effective pot odds. This can be quite difficult to determine in no limit holdem.

Obviously if you are calling an opponent's all in, or if calling will make you all in, or almost all in, then you would use the chance of making your hand at showdown.

This is the biggest problem with hot-and-cold simulators - they give you showdown equity, which needs to be compared against effective odds, NOT immediate pot odds. I see this mistake being made in the forums on a daily basis.

The other problem I see is that people don't really count all of their outs. They think that making their flush is the only possible positive outcome when in fact they may win by pairing one of their cards, making a backdoor straight, etc.