For sure on corrosion/rust - I’m experiencing this on a very small scale now - I’m working on repainting my old barbecue, it’s incredible how much time it takes to strip, apply rust remover, clean, fill, sand, prime and repaint the metal parts. Easily 5 to 10 times as much effort and time than it would take to paint fresh parts.
Also, a painting campaign also includes:
> ... a preparatory stage to search for the most corroded areas ... these areas are then stripped, and a first coat of an anti-rust primer is applied
...presumably there was no corrosion just after the parts were originally made.