Rust destroys the beauty of any car.
Usually the rust starts at the top of the wheel arch, and at the bottom of the arch near to the sill.
If the car is in good mechanical order, it makes good sense to take action and repair any rust on the body.
A nice, new comfortable car with a high safety standard and powerful engine costs a fortune and can lose £20.000.00 or more in the first year. A 10 -20 year old car may require some body rust repair, but that costs only a fraction of the amount that a new car will lose in the first year.