My thoughts on this can mostly be found within my
Quick Tip on Resource Management.Here's a transcript:
Today's tip is about managing resources like Action Points, potions, and powers.
There's two ways to improperly manage resources, and that's by playing too conservatively, or too extravagantly.
Let's handle the conservative approach first, which consists of not using resources during critical moments. This can sometimes be because a player forgets he has certain resources at his disposal, but more often, it comes down to play style. This is something I struggle with a lot in video games--I never want to use my potions, for example, because I'm always saving them up for that really big battle. So instead of using potions, I would just die, then have to load from my last save point and try again. Overly conservative players always have this notion that a bigger battle is going to be right around the corner, and we have to save up our resources for it, at the expense of our performance in this battle.
In D&D, there are no save games. If you lose a battle, you can't just go back to your last save point. So you never want to lose a battle, and look down at your character sheet and see that you still had resources to spend. Use the action point, use the daily power, second wind, you want to go down knowing there was nothing more you could have done.
Now, I'm not encouraging alpha-strike behaviour, which is what the extravagant approach entails. This is the opposite of being conservative--it's using your resources before the critical moments. In your first battle of the day, you just unleash everything in your arsenal and hope that you'll be able to take an extended rest before you run into a big battle.
They key is to strike a balance. You must constantly assess the situation. You need to use just enough resources to prevent yourself or an ally from falling in battle. With just one ally down, your party is at a tremendous disadvantage, because that's one less person dealing damage, or healing, or tanking hits. In a 4-person party, that means one of the four critical roles--defender, controller, striker, or leader--is not being filled. If you've got a potion, you can bring them back into the battle, but every round they are out of the battle means a decrease in your party's effectiveness.
Take-home message: Use just enough resources to keep your party members standing.