It’s kind of a fluid thing, IMO.
As a baseline, if a group wipes to the same thing 3 times, that’s when I personally feel okay leaving if I want to.
But I think leaving after 2 wipes (to the same thing) is also acceptable even if -I- would wait slightly longer. It shows that it wasn’t just a fluke wipe the first time, and 2 wipes in quick succession is a pretty dire situation for those who care about making the timer.
But, with that said, I ALSO think the further you are in the dungeon, the less okay it is to bail for that same criteria.
There’s a difference between leaving when the group wipes to the first boss in Shrine twice in a row and leaving on the last boss after 2 wipes after spending 30-40 minutes getting there.
When you’re that far in, I’d say it’s only reasonable to stick it out awhile longer. What’s 5, 6 more minutes of attempts vs the 40 minutes you’ve already spent there?
Obviously if no progress is being made, I get it. If it’s come to the point of “okay let’s wait 8 minutes for Heroism after every attempt”, I get it. Leave. But if things were just a little sloppy, try again.
And lastly, there’s the case of a group that’s not getting brick walled anywhere, but is still struggling every step of the way. I find it hard to quantify this one, but if every 2nd or 3rd pull is a wipe or has multiple deaths, I wouldn’t blame anyone for dropping. But like I said, I’m not really sure where my line is for that. Probably depends if I’m in the “Gearing” phase or “FoS / Raider IO” phase of Mythic Dungeoning.
Anyone who leaves after the very first wipe at any point is a massive tool and an idiot, though. 1 Wipe does not kill a timer (assuming it’s not a tank and healer combo dragging out a boss for 6 minutes before dying). Wait and see if it’s a failure that will be repeated or not rather than immediately tanking what is -usually- someone else’s key and everyone’s time.
(reminder: this does not apply to leaving for IRL reasons)