How useful are house rules, really?
I’ve noticed that in almost every game I’ve ran, house rules tend to be either unused or exploited. About the only house rule that gets used with any regularity is one where casters are allowed to add their spell casting stat’s modifier to damage and healing, and I still have to remind my players of the rule from time to time. I’ve added some pretty generous house rules during my time as a GM (including 4th edition’s “Inherit Bonus” system) that ultimately are ignored, and now I question the need for these things in the first place.
I don’t begrudge my players for not using my house rule; I get that Tabletop RPGs are already complex enough without the DM adding things into the mix. When it comes to making a campaign guide, however, the space used for house rules is probably better spent on fleshing out your world to your players. I’ve always thought that the worst part of Pathfinder / D&D books are the boring, mechanical stuff that fills the pages after the race chapters, so the notion of writing that stuff chaffs me, and ultimately gives my players very little for the amount of work I put into writing those rules.
So, why bother with house rules? What players seem to want (as far as I know) is fluff, something that will help them conceive a character in their mind; that’s what’s more useful, not extra rules for players to learn. Of course, house rule stuff as it comes up, but don’t prioritize them over world building when starting a campaign. Your players will thank you.