This came up in a discussion elsewhere. For the Stress economy to work the way it is intended, how many rolls per character would you expect to be making before changing scene and dropping stress to half Composure?

Most conflict scenes I've run seem to last about 4-5 rounds, so probably half a dozen or so?

For Conflict Scenes (intrigues, duels, skirmishes), about 4-5 rounds.

For Downtime Scenes, usually only 1 roll per player. Sometimes can be 2.

For Narrative Scenes, I usually do not really need rolls and just , well, narrate. Because in Narrative mode there is no "conflict".
Sometimes I just check skill score and narrate accordingly: Sure, your character knows about those plants because you have that skill.
It isn't like you need the player to roll a check, opportunities, strife etc for a simple random "check" in narrative mode. Just go with what makes sense.
But if I really, really do need a roll without a full blown conflict or downtime scene, I'll call for a one roll per player, basically treating it as a "short downtime".
Though, Narrative Scenes quite often end up turning into conflict scenes.

tdlr: strife economy is only for Conflict Scenes.

This is the only way we found to avoid water ring cheesing. Avoid rolls in "narrative scenes" at all cost.

I dunno. I do use rolls in narrative scenes but I'm not sure on average how many. It doesn't feel that many, certainly.

One exception - I do tend to use a lot of rolls where a narrative scene gets skill-intensive, that most obviously tends to happen in investigations; where you can have a player making 2 or 3 checks in quick succession.

That still rarely matters for strife unless they've come into it 'exhausted' - i.e. at half strife from a prior conflict scene - and/or there's something in the scene likely to trigger an anxiety, which can often result in one player being "..... and I'm done " and being reduced to assisting for the rest of the investigation (opportunities to remove strife in a narrative scene where you can't use calming breath and can't always insist on using your water ring for a given task can be few and far between).

I will say strife is a much bigger deal in any shadowlands campaign. One of the core rules for a shadowlands setting is that whenever you would gain any strife, you gain an extra point. That adds up fast - to the point that one character with a Fear of Corruption anxiety managed to go from half strife to compromised in a single survival check.

I guess I just play out investigations and such as narrative without checks. With the amount of weight in each rolls in this game, the opportunity, the strife etc, it feels really off to do many random check in a narrative scene. And it can become absolutely cheesy, for lets say a Water ring character starting to heal their fatigue and all strife over the course of 2-3 checks.
Though, IF the character wants to spend their downtime action to evaluate/investigate a case, then that is a roll. That roll includes many details.
That is the difference between doing 4-5 checks during an investigation for every little details compared to ONE check that takes a lot of time and that assess the whole situation.

Different playstyle I suppose. I use "downtimes" a lot (at least in term of rhythm, I think I run my narrative scenes with similar rules to downtimes). Basically, my PCs, outside of conflicts, will choose one thing they want to achieve through that day/night/period of time. End result is usually major (either good or bad or neutral depending on the roll).
For an "investigation campaign", I will run it more in a narrative way until the PC happen to have a decent grasp of their "possibilities" (investigate an area, interrogate someone, spy, gather lore etc). And then that becomes their "big action" that they decide to do.

as an example, yes, "in theory" a PC can decide to roll a Sentiment check for ANY NPC they meet... But I do not allow that, as I think it isn't in line with how the system function. If you want to use Sentiment on an NPC, it requires a downtime (or at least a good commitment to this activity). Basically, you spend time learning about the NPC, or talking to them, or whatever else (governed through the approach they use).

Hard to explain... but how I play it is always with only 1 major roll the PC want to achieve over a period of time. Then, that period of time is over, and we go into the next period of time.
Sure you can talk to NPC, check stuff etc and I will give hints or clues of what they can figure out based on their general abilities, but nothing "story defining" (that is reserved for the few Checks they will take)
It really adds weight to the choices they make (because they need to decide WHICH roll to make, instead of making dozens), and make the game/story runs faster instead of bugging down to checks after checks for 3 players to deal with minor things in succession.

I push the story forward very quickly, with big strides. With very few narrative rolls (that have as much weight as downtime rolls). Up until a "conflict scene" blows up.

Which, ends up making Strife only really relevant in Conflicts. But that is OK. because, the players generally DO NOT WANT to go into conflicts with only half their strife, they will be forced to be careful when doing their few narrative/downtime actions, and often, spending one of these few actions to trigger a way to heal their strife below half.

Also, a scene transitioning into another type of scene doesn't generally count as "ending" a scene.
That is how I manage strife economy, by forcing my players to use time, or non optimal actions, because they want to reduce their strife (passion, ninjo..). Because, the possibility of a conflict scene starting anytime puts pressure on them to stay relatively in "ok condition". And since there is only very few ways to lower that strife below half... It becomes a costly decision to take an action/downtime for that purpose. But very much needed in a lot of cases.