Playing a warrior in D2:ED I got my spirit up to 5 and left it there (later in the game I maxed Mana Efficiency, so I could summon the creature before a tough fight and have enough mana left over to heal if I needed to). I'd like to do the same in DKS, depending on how frequently I need to use special attacks.
I am not planning on using Rush Attack for retreat (and will not need it for attack); running and jumping should be good enough for that. I did use Rush Attack a couple times in D2:ED to get away from tough opponents (one fight because I needed to, and another just to take out the weaker opponents first), but I don't think it would be worth the skill point if that is all it was going to be used for.
