Do weapons and armor that improve spell and shadow damage improve every tick of damage using a DoT spell?
i.e. if I use Corruption, Curse of Agony and Immolate, will each tick receive +3 damage with an equipped item with "+3 spell damage"? I understand the separation in schools with Corr., CoA being Shadow and Imm. being Destruction, but I'm just wondering if I should continue my +sta/+int gearing or go for + spell/shadow damage