They are a necessary part of most games, and as GM’s something that we frequently have to deal with, either to address a shortcoming, plug a hole, or meet an unforeseen need. While a great many GMs are skilled behind the screen, that does not necessarily translate to their being adept at system modifications. So consider these guidelines when adopting your own house rules.

The Fiddly Bits

I’ve met GMs in my time who—like myself—love to understand and debate the interoperability of game mechanics; dive deep under the hood and see what makes a system work. Conversely, I’ve also gamed with my fair share who could care less about the underpinnings—they just want a game that works. Both are perfectly fine approaches (and everything in-between) and I’d even go so far as to say that the second group—if using a commercially published game—have an expectation that things will “just work.” Sadly, as we all know, that’s rarely the case.

Even designers are mortal and just like no adventure will survive an encounter with the PCs, no system will survive an encounter with a group of players…or a tweaker GM. Then there are the subset that like to tweak their rulesets—as is their right—even for no good reason. Man, I hate playing in those games!

So, putting my designer hat on for a moment, allow me to share my own philosophy when it comes to house rules or altering systems.

  • Make sure there’s a good reason. It seems obvious but unless there’s a really strong need to modify the rules—and you’re adroit at seeing all the downstream implications—do so only in the direst of situations. It isn’t uncommon for one “fix” to create a slew of new problems.
  • Emotionally divest yourself when possible and considering changes. Some changes may be emotionally driven, such as being adamant about closing a perceived loophole that a player found. Does it really need fixing or is this a case where you feel your base of power is being threatened
  • Simplicity trumps complexity, all things being equal. Or, in other words, Keep It Simple, Stupid (KISS). Don’t try to solve an issue with three die rolls and two charts when one roll will do. Yes, you may have to give something up to get there, but try to understand if that complexity serves the game in any way. Nearly always, complexity doesn’t; it just slows things down.
  • Have your change be appropriate to the game. A rule change in Savage Worlds isn’t likely as complicated as one that you might make for Rolemaster or D&D. Savage Worlds isn’t big into charts or deep simulationism, so your change shouldn’t go down that path.
  • Be internally consistent. What I mean by this is, whenever possible, use the existing framework that you have versus trying to create a new one. This is the largest “mistake” I see made: A Frankenstein melding of patches and fixes haphazardly applied in an effort to solve one problem introduces a litany of new ones. Plus it just feels out of place. The system may not do what you need it to do but there’s likely a way you can take the existing structure and mechanics, tweaking slightly to fill the void.
  • Don’t be afraid to admit to a mistake. Intellectual and emotional honesty go a long way here. Fess up when you’re wrong and strive to be fair and impartial. Your players will notice and it’ll go a long way.
  • Solicit other opinions, especially from your players. Best case you’ll get new ideas that you hadn’t thought of without having to do the heavy lifting yourself. Worst case your players will feel involved in the decision making process.
  • Build around a core resolution mechanic whenever possible and deviate for exceptions only when necessary. Essentially, exception-based mechanics. This helps eliminate complexity and unnecessary “forking” of rules.
  • I said it early but it bears repeating: strive for simplicity. There’s no one judging you for style points or how clever you are.

In thinking of an example to share I can’t help but go to one of my favorite games, Fading Suns. The Victory Point System (VPS) that it uses isn’t anything to write home about. It’s quite serviceable, however. It’s also something that just about every time I read about someone has tweaked the system. For good reason, however, as the system—as-is—does have its own problems with internal consistency.

For example, the entire game revolves around a d20 “roll under or on your target” mechanic. It’s straightforward, easy to grasp, and how high you roll without going over the your target (the Price is Right mechanics), determines how well you succeeded. Hitting your goal number exactly is a critical success. Easy, right?

Except combat takes a wild left turn when, after you make a hit, suddenly the system turns into a success-counting exercise. You roll d6s—the only time in the game you use a die other than a d20—and count 1s, 2s, 3s, and 4s, as successes for both damage and for armor soak. Every time I’ve explained this system to a player they’ve found it as jarring as I had when I first read the rules. In practice it just feels weird too; the game comes to a bit of a halt. (“Oh wait, I need my d6s now…”)

Now there’s a number of ways to approach this, not the least of which is just using the system as-is. But my point is less about trying to fix what feels like an abnormality but to highlight that it exists, even in the RAW. Personally, I’ve never felt compelled to try to “fix” this aspect of VPS, but many others have.

I’ve no doubt that you’ve tweaked your fair share of systems and I’d like to hear your thoughts as to how you approach such a problem at your own table below!