How often should the players roll Bluff when interacting with NPCs

Question

My party had secretly infiltrated a stronghold and we were Disguised (using magic) as the leadership of the place after eliminating the real leadership.

While rifling through the head honchos stuff we opened a chest that turned out to be alarmed and trapped. One of our party took some damage from the trap and the guards arrived soon thereafter.

Since we looked like members of the leadership, we went for a Bluff telling the guards it was a false alarm and that the injured character needed medical attention because he opened the chest before it was deactivated and before we could stop him ['That new guy, Bob, he just jumped the gun, whaddya gonna do with hired help these days?'].

Two of our characters did the talking and we each rolled Bluff -- poorly. Our basic message was a mix of truth and fiction (we accidentally set off the trap; one of is hurt and needs healing). The conversation with the guards continued and our GM had us roll Bluff again (I was secretly thankful since our first rolls were terrible). However, the other player didn't like this approach and got into a heated argument with the GM about how often we were rolling this skill check. This adventure does have us bluffing a lot and he doesn't like how often we roll in these interactions. The GM is fairly new and trying hard to stick to a script and felt that our characters were saying things in ways that were very different then who we were pretending to be. While I do think we are rolling a bit frequently, it's the GMs game and Rule 0 should apply.

Despite that, I thought I'd ask:

TL;DR

In a protracted conversation with NPCs where the players are lying, how often should they be rolling bluff? Every time they open their mouths, or less often ?

Answer 1

It's Up to the DM

Really, it is. Does the DM want everyone to roll every time a character opens their mouth? Or just when they're "selling an idea?" It's up to the DM.

As Often As Is Needed

This is a good rule of thumb. Roll bluff as often as it is needed. For me, whenever I DM, I only call for bluff checks whenever someone is trying to "sell an idea." Selling ideas can be just one movement, or a complex series of movements/"actions" (not game "actions," but doing things like "hand off of sword hilt, smile on my face").

So, in your situation, I would call for a bluff check when the guards entered, because you all are selling the idea that you're supposed to be here and a new guy hurt himself. If that's the only claim you're making, I would not call for any more bluff checks.

I would call for a new one if you claim to be leadership, because that's a new idea. If you went further and made a new claim, I'd call for a new bluff on that. If you claimed yet one more thing, that is another bluff check.

(This part is taken from Lucas Leblanc. Thanks Lucas!) The exception to the one-check-per-lie rule would be "fast-talking." If you a character is just spewing information at an NPC to confuse them or otherwise distract them, require one bluff check for the entire fast-talking "conversation." This really does conform with "as often as is needed," but deserves the mention here.

Answer 2

Many GMs struggle to run gainful social interaction well (cf. this article). In D&D 3.X there are 3 main social skills: Bluff, Diplomacy, and Sense Motive. Some other skills, like Disguise, are effectively a specialized version of one of these general skills in terms of social use. All of these general social skills can also be used for other purposes (like using Bluff to feint in combat), which further complicates things. Nonetheless each of these skills primary use corresponds to a specific kind of social effect, together giving 3.X players a number of mechanical options in conversation.

Bluff is the object-focused mirrored image of Diplomacy: where Diplomacy effects general changes in the target in the hopes of using them for some general purpose, Bluff effects a specific change, typically useful for some specific task.

When you use Bluff in the primary way, you get to convince the target(s) of something. If you succeed at your check (rolling against your opponent's Sense Motive) they are convinced of that thing. Unless they somehow become unconvinced, you do not normally need to roll again for that thing, ever. If, however, you want to convince them of additional things, you must roll once more for each thing you seek to convince them of. Generally, once an initial framework is constructed the circumstantial penalty due to unbelievability will decrease drastically.

Disguise is like a better version of Bluff that only works for one thing: convincing people that you are someone or something you in actuality are not. If all you were trying to do was stay in-character for your disguises, you shouldn't have had to roll Bluff at all-- your opponents would merely be entitled to another Perception check v.s. your Disguise total, since you had made them suspicious. You still could still use Bluff, though, if you wanted to, but the DC is a bit higher and you wouldn't get the nice perks Disguise gives you. If your disguise failed, you could attempt a Bluff to save it, but that's probably in the 'impossible' range, which confers a hefty -20 penalty.

If you only sought to convince the guards of a single Bluff-based thing, you should only have to roll once, though you might reasonably be required to roll again for other groups of guards. When you set off the alarm, the guards were probably un-convinced, which means you would need to make another check to that effect. Then, unless there were other things you sought to convince them of, you would no longer need to roll Bluff.

The above follows from the bluff skill description and the skill descriptions of various other social skills.