I make a point not to kill my players unless they make a habit of doing dumb shit, or it's "almost" happened a couple times already.
Especially if I get several good rolls or they get several bad rolls in a row.
The game should be fun for everyone, and if even one player goes home upset with the session I will have considered my night a failure as DM.
Not that I consider it a failing or even "bad" if someone else kills off their players. Everyone has different expectations from games and I've seen fantastic role playing of deaths before.
One player ripped their heart out of their own chest, chugging a health potion to stay alive long enough to place it in their spouse who had just died died, and another player healed the spouse.
They asked me if I would allow that and honestly it sounded cool enough that I was all for it.