I love house rules. I can’t really remember the last time that I ran or even played a game that was rules as written out of the box. But still there’s some that flinch at the thought.
You don’t need to be some master chef to of at least read a recipe or two. There’s one little sentence that appears all the time. “Season to taste.” You go to restaurant. There’s at least salt and pepper and probably some other condiments available. It’s all about seasoning to your taste. And that’s what house rules are. Making adjustments to fit the tastes of your table.
I’m not saying that this doesn’t a little skill, experience, and gut instinct. A GM may think that some thing is a good idea and it’s terrible. So change it and adjust. The other thing is communication. You don’t pour on the hot sauce when everyone else at the table thinks that garlic powder is too spicy.
As a GM, you have the responsibility of knowing the rules and how to adjudicate them. You also need to know your players and their tastes. And just because everyone wants to play a specific game, it’s OK to mess with those rules. The key is communication. Know what you like. Know what the players like. And then season your game to taste.