[3.5] How much material is nessicary?

[Drakevarg]

My question is admittedly extremely abstract, since it's a hard thing to quantify. The full, explained question is:

How much plot material is nessicary to run a single session of average length?

I'm asking because I'd rather not have enough for about half a session's worth of play and be stuck ad-libbing a story of rapidly declining quality. For example, my current plan is to start with a heavy RP session involving interacting with their friends and family (to develop empathy for when I brutally murder and zombify the lot of them, of course), followed by a second session of exploring the ruins of their village.

The reason this concerns me is that in different campaigns I've had radically different experiences in this regard. In one, quite literally the only things that happened were a knife fight, then being tossed off a cliff and climbing back up it, followed by an avalance. And yet I currently regard that as one of the most exciting sessions I've ever been in.

Another one gave me sufficient time to explore what appeared to be a mix between a fortress and that spa from "Spirited Away", then fight a small army of bandits, then fight a pair of minotaurs. (I can't remember if everything that happened after that was part of the same session or not. If so, then we also managed to get to town, take a ship, fight off some pirates, die horribly when the pirate ship exploded, get resurrected by an epic level cleric, head to another village, travel with a bison herd, find an ore refinery camp, fight a shadow mastiff, fight a skeletal dragon, fight off some cyborg things, and then escape on a mine cart.)

Obviously this is an opinion question, so I suspect I'll get alot of variation in answers.

[Jack_Simth]

It's an essentially impossible thing to quantify.

See, it varies, based on the group (and the DM) and the mood at the time.

An individual plot point might take all night... simply because the group focuses on it, hashing over details. Or you might go through five or ten in a session, simply because they turn out to be less interesting to the group than anticipated.

[Sindri]

And of course there's a good chance that your players will ignore your nice plot points altogether and either charge ahead uninformed or focus in on something irrelevant that you have nothing prepared for.

[Drakevarg]

Given that I map out everything interesting in a given area, if they just ran off in a random direction they would find the following narration:

"You find trees. Lots of trees. Oh, and a squirrel."

[PersonMan]

I would advise planning twice as much as you think you need. If you go faster than expected, you have stuff. If you don't get much done, well, less work for later, right?

I can prepare very little for an actual session(stats, ideas of what they'll face) and get through it, but this is what I'd advise for someone who can't do that. I hope my advice still applies.

[Drakevarg]

I would advise planning twice as much as you think you need. If you go faster than expected, you have stuff. If you don't get much done, well, less work for later, right?

Hm. Yeah, I was thinking this was the case. Never assume you have enough prepared.