What's the Frequency, Kenneth?

First: welcome to all you GURPS Day readers who have found their way here from Gaming Ballistic!

There is something that certain other games do very well, that GURPS seems, on the surface, to lack rules for. GURPS is replete with limitations on how often you can use abilities in game — but those limitations are all very concrete, based on time in game: once per day, once per hour, &c. What seems to be lacking is meta-game limitations: per scene, per session, &c.

GURPS does have in the Basic Set certain abilities usable based on real time: once per session (Serendipity and Wild Talent) or once per hour (Luck and Super Luck). GURPS further defines the “Game Time” modifier, for converting those advantages from real time to game time; it suggests that once per session might be equal to once per week of game time, or that once per hour might be once per day — the exact ratio is left up to the GM.

This is defined as a zero-cost enhancement, with no real impact on the value of the advantage — arguably, this means it should work just fine in either direction, converting game time to real time. Thus, the only question that remains is “What length of time fairly corresponds to a unit of meta-game time?” Let’s see if we can’t answer that.


There are four broad categories of frequency:

Once Per Scene
A scene might be a single combat, a dinner party, or a meeting of some sort. It’s a significant limitation on any combat power, effectively amounting to a single use for that combat. This is arguably the most variable limitation; Game Time could be much more limiting if several short scenes happen in quick succession, with little downtime, but Meta-Game Time could be much more limiting if a single scene stretches out for most of a day.
Once Per Session
The literal definition of a session is obvious, barring all-weekend-long extravaganzas where the group games until the wee hours, sleeps it off, then gets right back to it over breakfast1. It usually contains several scenes, so a once per session ability has to be used wisely. The Game Time modifier suggests that once per session is equal to one week of game time — the only rules-as-written data point we have for Meta-Game Time.
Once Per Adventure
A proper adventure might be a single session, but in my experience is usually two or three or more. The exact definition is vague for some groups — for a classic dungeon crawl it’s simply one module, but other groups can usually make it work as one (side)quest or one dungeon. For groups that don’t hand out XP every session, this will almost undoubtedly be “every time we get XP”. This is rarely enough to be a significant limitation, nearly as much as an ability that costs character points to use.
Once Per Campaign
For a group that retires characters after a single campaign, this is effectively one use ever. GURPS already defines that as a ×⅕ multiplier to the cost of an ability.

Once per scene seems to best translate to once per hour of game time: Takes Recharge, 1 hr., -30%. Once per day might better suit slower-paced campaigns, but once an hour seems safer given that the action can speed up in a glacial game of political drama. Either way, adding our hypothetical Meta-Game Time modifier turns this into Once Per Scene, -30%.

Once per session is already defined as once per week of game time: Accessibility, 1 day/week, -35% + Limited Use, 1/day, -40%2. This one could be changed up to once per day, but that brings it very close in price to the more-useful once per scene. Every other day might be the best point for it: Accessibility, every other day, -20% + Limited Use, 1/day, -40%. Which one I use would depend on how much a given group covers in a session and how close to RAW I want to stay, but either way, adding our Meta-Game Time modifier turns this into Once Per Session, -60% (or -75%).

Once per adventure is the least useful of these. The lowest we can bring it and still stick with RAW limitations is once per month of game time: Accessibility, 1 day/month, -40% + Limited Use, 1/day, -40%. This conveniently maxes out the limitation cap (assuming no other modifiers), which seems fitting. It also makes a reasonable progression with the -60% version of Once Per Session, but seems uncomfortably close to the -75% version. Again, adding our hypothetical Meta-Game Time Modifier turns this into Once Per Adventure, -80%.

-30%, -60%, -80% — that’s a progression I can live with. Whatever ratio you decide to use, I hope this helps people who want a more “dramatist” feel to their games.

*[RAW]: Rules As Written


  1. I miss those weekends. This pesky thing called real life got in the way a few years ago. When we’re all in the retirement home together, though… ^
  2. You need both limitations, both for a fair price and for it to work right. Accessibility, 1 day/week lets you use it all you want for a single day, then it shuts down for the rest of the week. Limited Use gives you one use on that given day. ^

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