We do a round-robin system, where one person DMs out their campaign, then someone else does, carrying on the same player characters, the same world, etc. This can be really cool--you get the chance to see how each person takes on the responsibility of running the game versus playing a character, and that can give some neat insights into their personalities.
But it's not without its snags. Right now we're on our second DM for this world/set of characters. The first DM ran what was basically a really long dungeon crawl, except some of it happened above ground. We came out of that after six months of playing with fifth level characters, and a decently tight-knit group. That DM was pretty free with magic/magic items/masterwork items--in that if it was in the book, it could probably be bought, looted or found.
The DM we're playing with right now runs a bit tighter game. He's running a quest-type-campaign, and I expect it will last longer than the first. His view on the books and the items/monsters/rules inside is very similar to mine: they are guidelines for balanced campaigns. If he wants to switch the powers/features of the chromatic dragons with the metallics, well, that's great! I mean, none of our characters have ever seen a dragon, so how would we know that that particular dragon has ice blast at 4d6 damage for a breath weapon?
On of the players is very much a book-gamer; he thinks that if it's in the book, it's readily available. He has this notion in his head about getting poisonous retractable armor spikes, and he'd gotten really hung up on this idea that he just had to have them. The first DM knew this, and really didn't say anything about it--the party wouldn't have had a chance to do anything concerning armor or weapons til the new campaign. The new DM doesn't think the armor spikes are something that would just be lying around, or even easy to find.
That player is really uncomfortable in the new campaign. He explained to me--if the DM keeps changing the rules from how they are in the book, how is he supposed to know how things work? How is he supposed to play his character?
This spurred a long conversation between he and I, which I can't find at the moment. The gist, though, was this: does he know all the rules for real life? He misunderstood and cited some laws--but those are only applicable to lawful good characters. What are the laws of the universe we live in? He admitted that he didn't know them all. Next game, he had a lot better time--he started playing his character as a guy who knows more than most instead of the guy who knows everything. Oh, and he let the poisonous retractable armor spikes go.
How do you guys deal with players who think their characters know everything? How do you deal with players who are in the game for decidedly different reasons (exp. points, loot, levelling up) from the rest of the players (in our case, fodder for fiction writing for most of us)? That second part is what reminded me to post this--I don't think there is One True Way to game, but I do think that some of the different ways don't mesh very well. Oh, and do any of you do the round-robin thing? If so, how do you manage having characters at proper exp. levels with the right tools for the level of campaign they're going into next? Example: DM #4 is planning on running a very high-level game and needs our characters to be between 10th and 15th level for his game, but the current DM and DM #3 think they'll only have levelled us up to 8th or 9th level.