A question about luck

[Futumsh]

Hi guys can someone explain why no people use luck/reroll enhancement in running Orrick or Hydra? Is that it will lower the chance to loot arcane item? thanks!

Luck never lowers your chance to loot an arcane. If you roll an arcane with your initial roll, no matter how much luck you have, it doesn't reroll.

Luck rules... If your loot reroll would trigger:
* If your initial roll is an Arcane or Heroic, you don't reroll.
* If your initial roll is common, rare, or epic, and the loot table has things of the next rarity up, you get one of those.
* For all other rarities of initial roll, you roll again from everything, and you get whichever is more rare of your rolls.

For luck purposes, the 'more rare' order is common < rare < epic < legendary < mythic < vanity < spirit < set < arcane < heroic.