If you apply Plasti Dip to your whole car and do the job properly then it should last at least 3 years on the whole car before it starts coming off.
However if you keep your car in a garage out of the weather when not driving it then the Plasti Dip may last 10 years or longer on the whole car.
Plasti Dip is supposed to last at least 3 years without the need to touch it up as long as you apply the Plasti Dip properly and make sure the surface is clean and dry before applying the Plasti Dip.
I've never applied Plasti Dip to a whole car before but when I did apply Plasti Dip to parts of my own car it lasted for 3 years and then I needed to touch the Plasti Dip up.
I'm sure that Plasti DIp would look very good on a car when it's on the entire car and I never thought to do that.