Rule of Three

Chromatia is a world oversaturated with magic and magic powers, and so it was the forces that maintain order and balance imposed a restriction on all things in the realm. Any item with sufficient magical power to produce a tangible effect without being destroyed in the process cannot affect the same person more than thrice in a given day.
  For example, the popular Clockwork Amulet normally permits a creature wearing the amulet to replace one attack roll with a roll of 10, for better or worse. If you possess multiple clockwork amulets and have somehow devised a means to wear several, you can benefit from no more than three in a given day. If you try to use a fourth amulet, it simply doesn’t react.
  This does not effect consumable items, like potions or scrolls, given the items’ otherwise limited use, and has no effect on items that require attunement to use (considering you cannot attune to more than one copy of an otherwise identical item).