Plot armour.

[Cephus]

I don't think it counts as "plot armour" when a main character survives dangerous situations.

They have to survive them realistically though. I've seen lots of amateurs writing books where the hero survives absolutely everything, no matter how absurd. The bad guys are shooting at them? They dodge every bullet, even with no cover. They're in a tsunami? There's a convenient rowboat nearby and they're just rowing furiously over the crest of the tidal wave because the writer needs them to survive. Meanwhile, the readers are just rolling their eyes because the whole thing is absurd. I get so tired of really terrible writing because the story needs to happen. Maybe the writer needs to write a better story.

It's one reason I stopped reading most fantasy, because it's so common for authors to write themselves into corners and then invent a new magical spell to get them out of it that comes out of absolutely nowhere. Or they'll just reinvent their magic system on the fly so it can suddenly do things it could never do before, so they can get where they want to go. That is just bad writing.

You don't have to kill people to prove that characters are mortal, but it does no good to put anyone in a dangerous situation if the reader knows there will be no consequences. That's way to common out there.

[vranger]

it's so common for authors to write themselves into corners and then invent a new magical spell to get them out of it that comes out of absolutely nowhere. Or they'll just reinvent their magic system on the fly so it can suddenly do things it could never do before, so they can get where they want to go. That is just bad writing.

... which is exactly what Jim Butcher does a few times early on the The Dresden Files ... and has himself said he thinks the first few books suffer from his inexperience at the time.