Hi everybody, pretty much what the title says: I'd say before, when a player wants to decide to add + 50 or + 100 to a die roll, and after, if a player wants to subtract -25 or -50 to a crit she/he just received. What do you think and suggest?
Whenever the player (or NPC if a GM gives fate points to an NPC) wants to use them. Before a roll, after a roll, even after the total has been added and the result looked up.
The only limitation is no retro-active changes. Once an action is over and somebody else takes their turn in the round, fate has been decided.
The whole point of a fate point is it allows characters to change an undesirable outcome. They're a scarce resource, so there's no need to nerf them...if a player wants to waste them on something trivial, let them.
The HARP rulebook says:
Fate Points may only be used in situations where success or failure will have an immediate and important impact on the character such as during a confrontation of some sort; they may not be used for something as mundane as the crafting of an item or other non-stressful situations.
Stress and fateful situations are reasonable limitations, but context is important. There are situations where making a crafting roll might be an extremely stressful situation that determines whether they earn the title of Journeyman or Master, or become a Failed Apprentice.