I suppose the next thought would be “shouldn’t all steel items show rust then”? I mean, I’d think all steel items (even partially made of steel) that are left OUTSIDE should rust over time. Outside is defined by exterior tile vs. interior tile. Some containers could protect their contents, but the container itself could be subject to rusting, eventually losing that protection.
The rate, or rust check could be made once every season too, if once a year seems too slow a rate. Or once every 3 seasons. Maybe even set up an option for it. Should the rust rate be based on days or seasons, since season length is a setting. Or both perhaps, such as “Advance rusting every 30 days or 1 season, whichever comes first.” Or let the player choose whether to use days or seasons.
Items or vehicle parts could already start out at very rusty stage (some parts, not all). I mean, we could generally come across two types of vehicles - ones that have been used recently, and then the long-ago abandoned wrecks, which would show stage 4 and 5 rusting already upon world generation.
First and foremost I’d want this to be a mod. But having a “mod” integrated into the game might help with troubleshooting and debugging if we accept the idea that a higher number of potential mod combinations potentially makes troubleshooting more difficult.
And I can already think of some potential (but hopefully perfectly solvable) issues:
- Fuel and liquid tanks. If they rust completely, should they leak their contents?
- Ammo (steel casings) could be immune to rusting. Or it could increase jamming rate, or even damage the gun.
- If the player drives a car outdoors when the season changes, the vehicle might suddenly collect some rust spots. But locating them and clearing them might become a chore. So that would have to be solved.
- Same for worn items. Some apparel, and not to mention weapons, do contain steel. Do we make these carried items immune? Or would it be neat if your favorite machete suddenly develops a tiny rust spot?
- If we extend rusting to all equipment, should it have some effect? Cutting melee weapons could lose damage, or become more easily stuck at later rust stages. Rust is also a hygiene risk, since bacteria can nest in the jagged surface of rust. Should sufficiently rusty tanks of clean water carry a risk of becoming dirty water? Should sufficiently rusty cans of food become spoiled? A rusty blade could also be an infection risk if used by hostile NPCs on the player. Where my tetanus shots at? I mean, assuming the syringe needle isn’t rusted…