I answer your question the way I decide for myself.
Which event is more rare?

I've never broken a leaf spring, and only 2 coil springs. It seems leaving firearms cocked is of no consequence generally or at least from my experience.

Damaging firearms from dis-assembly, reassembly, is common. So, I leave them together after cleaning/wiping.
Crumbly, oily, stocks are real common, so I do as little lubricating as possible.

YMMV, naturally.

Out there doing it best I can.