There are many occasions where skill is not the answer nor can every eventuality be planned. In some cases i am willing to make a call based on things going on in the campaign, other times, i resort to making the characters perform a “Luck Roll.”
In some games, I have added a Luck Stat that is figured like any other stat and rolled like any other stat roll in that system (pending the system at the time).
Other times I have institutes “Charisma as Luck” where any time a luck roll was needed i had the character roll against their Charisma.
Currently i am using the “Luck as Luck” system where the player rolls a d20 and the GM rolls a d20, higher wins, ties are minimal success, successes or failures get incrementally better (or worse) for every increment of 5 the rolls differ.