What comes in with a lot of rust is old VW campers which are often parked near the sea. The boy sometimes welds an entire front panel on these as the rust around the screen gets too bad. people will spend 3000 pound welding those old vans including fitting new front floors and the step.
On average, the modern cars are in need of welding repairs at 15 years locally.
Mud flaps have not been used or supplied by makers for near 40 years as they cause severe rusting along the bottom edge of the sills when water clings on instead of blowing away on a journey. The plastic inner arch cover are sufficient to keep rust out of the front arch area.
At the garage, the boy sand blasts the bottom of campers and applies waxoyl rust proofing but its quite a pricey job once the vehicle has started its decay.