Hello! This question is going to sound very uninformed, because I am very uninformed here. I'm approaching the Job mark on all my classes, so I will start playing around with WHM and SCH (AST eventually) soon. Now, I periodically see stories or rants about people overwriting each other's buffs or shields or regens or what have you. Rather than become a story for Reddit, I'd like to nip this in the bud:

What stacks, and what doesn't? What overwrites? What just overlaps? I know this is vague, but my knowledge of healing classes is rather limited outside of the buffs I see on myself while tanking, and that hasn't helped me figure this out.

Edit: and while I'm here, does the PLD shield from Divine Veil stack with healer shields?