Why would I want to re-roll a successful roll? (AKA: Fishing for results)

UnitCrunch notifies you when you've configured a modifier that could potentially re-roll a successful roll. It only notifies you, it doesn't stop you.

These sorts or re-rolls can be useful when modelling an in-game strategy known as "fishing". This is normally when an effect would be triggered on a specific roll (e.g. a mortal wound on an unmodified roll of 6) and an available re-roll makes it worth trying for those 6s despite the risk of turning some previously successful rolls into failures.