Resource management

In DDO, you can't just sit down and wait to get your resources back. The party has limited resources in some aspects. If those resources are empty, the mission will fail. The most important limited resources are hitpoints and spellpoints. If you have a divine caster in your party that has a cure (or heal) spell, spellpoints can transform into hitpoints. The same is true if you have someone with a repair spell and a Warforged. This makes spellpoints the primary limited resource. If an Archer has enough bolts (or arrows) with him you can think of that as an unlimited resource. So if the party has the choice between using arrows or spellpoint to solve a mission, the best resource management would be to use arrows. Even if there is a spell that can find a door, there may be another class that can find the door with skills. That is the right choice for resource management. So don't use up the spellpoints. ...

Bards and clerics have limited ability to give spellpoints to other people, but cannot function as a serious mana pool. (Clerics can have Divine Vitality, to convert Turn Undead uses into small mana boosts, which is good when there are no undead, or for any cleric with low charisma) Also, the need to conserve sp is part of the reason wands are useful, especially of healing (wands have a slow cast rate, and don't work well in the pace of combat)

... Actually, the primary limited resource is the Rest. Rests can convert to hitpoints and also spellpoints (and daily-use abilities too). So, your main resource management is about what shrines are available, and when to use them. As a very simple rule of thumb, a caster should try to never rest if he has spellpoints left. If you're going to rest, find something useful to do with those points: heal someone mainly, but also buff someone (who is not about to rest herself)