Decomposition rates?

[Dalin]

Originally Posted by Dalillama

How long might a sword last, if it saw regular but not constant use, near-exclusively against opponents without metal tools? (some opponents may have e.g. unnaturally hard scales/carapaces though)

I don't know about a sword, but I do have a hunting knife that my dad used as a boy scout and then passed along to me when I joined the scouts. Never used on metal, but heavily used for whittling, food prep, etc. Sharpened regularly with a whetstone (perhaps too regularly when I was young). The blade is still excellent, but it is noticeably smaller than when it was first forged (not that I saw it back then, but I've seen similar ones) and, indeed, the blade looks a bit funny compared to the grip. Despite the fact that the knife is nearly 80 years old, it probably only saw heavy use for two decades, maybe a bit less. I would guess it would remain useful for another round of scouting, say 10 years of regular use.

I'm not sure if that experience has any relevance to a sword. A sword blade is longer, and thus more vulnerable to damage from drops and poor strikes. My guess is that a sword that sees regular combat use, even without being used against metal weapons, would degrade fairly rapidly.

[Dalin]

Originally Posted by Turhan's Bey Company

If a part of your dungeon is occupied by unintelligent life (evil snakes, giant insects, venomous hedgehogs, etc.), organic materials will last perhaps as little as a few weeks, certainly no more than a few years.

The key factor here, as it is in a number of environments, is life. If a cave is the lair of various critters, they'll be breathing a lot, exhaling water vapor, which is pretty damaging to anything organic over the long run. Far more importantly, though, they'll be living in it. Garments and books find themselves used as nesting material, leather gets eaten, wood gets gnawed on, and there are secondary attacks by lesser vermin living in the environment along with the big monsters.

Ah, ok, this should have been obvious to me (considering how often I combat the vermin trying to destroy my home) but I hadn't thought about it. So even if a dry dungeon became uninhabited (by the cultists or whoever) for a few centuries, it's likely that all the usual critters will make short work of most organic matter (like robes in a wardrobe).

Originally Posted by malloyd

If the environment is dry, sterile and free of ultraviolet (or higher energy) radiation, most stuff could easily last multiple thousands of years.

Got it. Preserved organics require either regular upkeep or a dry, sterile environment (like a sealed tomb in a desert). Or magic, of course.

Thanks so much for your thoughtful replies.