It's not just a question of "have you done it in your game or not", but rather I'm wondering about the rationale behind the rules.
What's the desired effect of this restriction and what effect on the game does it have if it's removed?
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Sign up to join this communityIt's not just a question of "have you done it in your game or not", but rather I'm wondering about the rationale behind the rules.
What's the desired effect of this restriction and what effect on the game does it have if it's removed?
Stress is a pacing mechanic. It's a way to control how fast and intense your conflicts are. Messing with this changes the kind of stories Fate tells, by changing how seriously PCs take conflicts.
Increasing the speed at which you can use stress boxes shifts the pace of conflict. Characters with multiple stress boxes become much less squishy against large hits: they don't have to absorb stress with consequences very often if they can leverage all their stress boxes against a single attack. Since usually NPCs have fewer stress boxes than PCs, this means that PCs become less concerned about the fallout when they enter conflicts. This, in turn, reduces the "dramatic" part of the dramatic/proactive/competent paradigm for Fate PCs.
(This started as a comment on BESW's answer, but I ran up against the character limit, so...)
In addition to the combat balance considerations, I think there's a narrative/game design aspect to this question:
With the current rule, Fate combat often involves several turns spent setting up beneficial aspects. DFRPG calls this 'maneuvering', Fate Core rolls it into the 'Create an Advantage' action. Once they're set up, one character tags them all at once for a single powerful attack that either takes out the enemy, or at least forces them to take consequences.
This is (IMHO) a good thing, and I get the sense that it's part of the intended combat dynamic for the system - it helps keep combat interesting and narratively-driven.
If multiple stress boxes could be used per hit, it would become more effective to simply attack every turn, and just try to gradually run the enemy out of stress boxes. By removing the incentive for maneuvers, you would also be removing an incentive for players to help construct the narrative of combat. The game would be less interesting that way, I think.