how long should a setting back story be?

[Lord Foul]

Thanks.
I guess what I really need to know is, how much do players want? As a GM I always have a long and sometimes complex history of the wider region, just so I don't get caught out. I like doing it, and it comes easily. Same with the geographical features: I like planning for the four corners of the compass, knowing full well they might never go there. It's never wasted, because any reuseable features I just have on flash cards to pull out as needed.
So I'm always curious how much a group of players wants at a time.
I'll never give them the whole history. Some things are best left as mysteries.
So it gets down to, how much does your PC need to know?

Enough to answer my questions without holding up the game to think about it.

As a player, that is 100% my answer!

I agree in part, but I really want a bit more than that. I want that, yes, but I also want to know that there is more out there to be learned and explored and found out. I expect there to be plots and counter-plots and, crucially, for there to be benefit from the act of logical thinking. In other words, if I put the effort into gathering information and reasoning from it, I want that to actually have a chance of discovery, not just be wasted effort.

[John]

These days I'm good with knowing about the last five minutes of what my character has been doing and going from there.

As long as the DM is good with "oh yes, of course the guard captain is your ex-brother-in-law!" type things as we go along. Which everyone I currently play with is, because nobody uses it to say "oh yes, of course I left exactly the spell scroll I need right now in a bug-out bag five feet away from where I'm standing."

[VaMinion]

Thanks.
I guess what I really need to know is, how much do players want? As a GM I always have a long and sometimes complex history of the wider region, just so I don't get caught out. I like doing it, and it comes easily. Same with the geographical features: I like planning for the four corners of the compass, knowing full well they might never go there. It's never wasted, because any reuseable features I just have on flash cards to pull out as needed.
So I'm always curious how much a group of players wants at a time.
I'll never give them the whole history. Some things are best left as mysteries.
So it gets down to, how much does your PC need to know?

Enough to answer my questions without holding up the game to think about it.

...and without becoming a straitjacket.

But otherwise this.

[keithcurtis]

I world build from front to back. I come up with "the world as I want it", and then write a history that caused it to become that way. This usually gives me any details I need, fixes logical inconsistencies or fill holes. Example, I want A to be at war with B, but need a reason, and compelling reasons for those reasons. This allows me to quickly have motivation for NPCs to hate/like the PCs, for patrons to desire their services, etc.

I write most of this pretty openly, and make it player-accessible, but I don't expect any of them to read it. I provide abstracts for that: Here's a timeline. Everything on the timeline has a larger entry in the campaign bible, but you really don't need to do anything more than read the timeline. And realistically, one can build a character without even doing that, but they will likely be missing campaign hooks.

Finally, I write with a "Circle of Lamplight" approach. Things which have impact on the players, recent, or local events are lamps. They get the most detail or illumination. The farther you get from things that will affect the game narrative, the less detail.

Prehistory is a paragraph. Recent history may be pages. My whole campaign bible is probably a small to medium sized book. That entire book can be summarized in one paragraph for players who don't care about such details.

Finally, the real reason I do all this is A) so I can be consistent, B) so I can quickly decide motivations and actions of NPCs and groups for when the players do something unexpected, and C) Fun—I like to do it.

[xsgtdanusmc]

If you use a pre-written setting/IP (D&D's Forgotten Realms or Greyhawk, HarnMaster's Harn, Battletech's universe, DC or Marvel, Star Wars, Star Trek, etc.), most of the work is done for you. You just need to know the corner of the universe you're starting the game in.

If you are building a homebrew setting, I'd start small and build my way out, then add/fill in as needed the back-setting to get the game off the ground as Keith mentioned. Allow the players to build some of it too, like Chad does. No sesne in you doing all the work.

[Nobby-W]

I think it's worth putting a bit of effort into the big picture stuff about your setting, but this gets into diminishing returns pretty quickly. Nobody really cares who supported King Arbuthnot III at the Battle of Lower Throcking unless it has some direct bearing on the adventure at hand.

It's worth doing some broad brush strokes - significant events, factions and features of the environment, but don't overdo it. Chances are nobody will read it, and stuff just made up in isolation like that tends to be a bit sterile. Start with a bit of big picture but put most of your effort into stuff that directly supports your adventures. This is stuff your party will interact with directly, and you can evolve your setting as you go, which will make it feel more lived-in, as well.

Chances are that if you hand your players more than a few pages of it all at once, most of it will go in one ear and out the other. From that perspective, it's better to drip-feed your setting canon. This also gives the party a sense of discovery. Liberal use of Chekhov's guns lets you use show-don't-tell techniques in this process, a process that I sometimes call 'Chekhov's Arsenal.' To further torture the Star Trek analogy, killing off redshirts to show how the monster works, prior encounters with different aspects of the setting and suchlike are an interesting way to reveal setting canon to your players.