The cause of your dents, is you.
If you park inconsiderately, people will leave you a reminder. If
you park thoughtlessly, without thinking that other's might dent
you when they open their door, you will be dented.
Depending on how careful you choose your parking space, determines
how many dents and dimples you collect. I collected none so
far.
If you insists on parking thoughtlessly, the best solution will be
to install hundreds of pointed half inch studs all over the sides
of your vehicle. This way, people will park far away from
you.