I started a new game of AD&D 1st Edition today, and fully cognizant of the lethality of the early levels (8 HP on a level 1 Fighter versus monsters that roll 1d6 for damage!), I decided to take a page from 13th Age as a means of making near-death hurt, without making it into a complete “you’re dead and done during the first round of the first combat”
Simply put, when the player was about to take a hit that would otherwise reduce them to 0 HP and death, I asked the player to pick an item that the potential killing blow would destroy, and then left the player with 1 HP.
In this case, it was the Assassin player’s leather armor. Their AC worsened from 5 to 7 as a result, and they had to complete the rest of the dungeon effectively unarmored, and I thought it was a neat way to introduce loss without making it irrevocable.
That said, leather armor only costs what, 5 GP? Easily replaced, right? But consider the implications once the character is equipped with a plethora of magical items. Will the Fighter let their Sword+2 melt for the sake of surviving a dragon’s flame breath? Will the Magic-User be willing to de-power their magical ring or tear a page from their spellbook to avoid the next deathtrap? I think this is a more “character building” solution to avoiding unwanted too-early deaths beyond my usual houserule of “add 10 HP” or the likes.