How do you handle party stealth? Does each character roll a stealth check? Do you have the best PC make a single roll? Do you allow helping or other types of modification to a single roll? How do you handle these types of challenges? How does it work for your party(ies)?
I've always had a challenge or uncomfortableness about the RAW methods. Having every character roll and using either passive or active perception makes sense, but means most parties have a heck of a time actually being stealthy. Having only the most stealthy roll means that most parties will always succeed (esp if the party has a rogue with expertise and reliable talent) even when one of the members is a walking tin can with a dex of 8.
First off, I determine whether a roll is even necessary, and whether it is even possible. There are situations, like sneaking past drunken nobles after dealing with the guards, where I'm not even going to ask for a check; so long as the conditions for Hiding are present (or have been orchestrated by the players), then it's automatically successful. Likewise, there are situations, like crossing an open battlefield at twilight, where so long as the conditions for Hiding remain lacking, no roll will make Hiding possible. That's a very important disclaimer.
Secondly, if I have the entire party attempting it, I almost never will make it boil down to "if one of you fails, then the alert goes to full and your infiltration is blown." Because odds are every group will have a tank in heavy armor who sucks at Stealth. EDIT: I should clarify that there are two "answers" I use to this issue... (1) The first is setting smart stakes/consequences to failure that don't go from 0 to 60 (i.e. that aren't totally black and white). (2) The second is much more situational (and thus I can't present a hard-coded formula for) and involves stuff life having one player roll, Helping others, etc.
Thirdly, it depends on the scenario and how much prep I've put into it. What I mean is, if this is just a guard patrol or random encounter or side quest the PCs have gotten themselves into, then a RAW group Stealth check compared to passive Perception (or active Perception) is what I'll use. If half or more of group succeeds, then entire group succeeds. Results tend to lean binary: "sneak past or be discovered."
Whereas if the entire scenario is based on infiltration, then I'm prepping more, and I devised my whole system/approach to these sorts of stealth infiltrations. I'll link my example PDF
Assassinate the Lizard Emperor which breaks down that approach, but basically it's (a) take an average of everyone's Stealth for initial penetration through rings of concentric defense, but thereafter treat Stealth as a save used only as a last resort when you draw attention to yourself, (b) focus on the creative challenge of creating decoys, snuffing candles, knocking out sentries and dragging away bodies, creative spellcasting, and other endeavors to
create the conditions ripe for hiding, (c) include some kind of a "heist planning" indie mechanic.
