My question is rather simple, but we can't quite put a finger on the correct answer. Items such as the Lucky Cigarette Case ... can we use them on other player rolls or just our own? The text says to add 1 to the result of a single die roll ... but doesn't specify on whom you can use it. Any help would be neato, thanks in advance.
No, unless an item specifically says it can be used on other investigators (e.g., "Choose an investigator"), it can only be used on/by the person holding the item.