[Domitian]

Calling all users who have bought cars in the '90s and early 2000s and have them spotless to this day - what is the secret?
My 2004 A4 is already rusting on the driver door and around the front wheel wells, in the former case it started internally with a bubble and then forced the exterior paint out, in the latter first the paint chipped and then the rust came.

I of course don't want this to happen to my 2023 Camaro in 15-20 years time. I daily drive it in the winter so it is exposed to the elements.
Ordered PPF for the front (hood, bumper, mirrors, etc) and it's already saved me from getting scratched once, and they have very long warranties, so I recommend the process. I suppose PPF would protect against rust in that it shields the paint from getting old, but the price of a full-body PPF approaches or exceeds $5000 CAD in my area.



What are tips and prevention methods could I take now to have this car, despite its heavy use, last decades without rust chipping away at its foundations?