So I think I know the answer to my question already. I just want conformation. I've always stuck to solo until recently so it's not really something I've had to think about much. So for example, I'm in a pug 4 man dungeon. I use caltrops and a few seconds later so does another member of the group. So I'm doing DoT and reducing movement speed by 30%. Is the other person also doing the same DoT and reducing movement speed a further 30%? How about with debuffs? I hit the target with a surprise attack causing major fracture. If a group member then hits them with focused aim and applies minor fracture. They stack right? But if the other person had applied major fracture that wouldn't stack and it would be pointless us both applying major fracture?