I get it! I used to be a distributor for Optimum while I owned a detailing business. I sold Optimum No Rinse (ONR) for almost a year before I could stomach using it on the cars I was washing. Once I started the pressure washer was history. I try to stay agnostic in my answers, but I really do believe in and use this product on all of my cars. If a car is really dirty, say with mud or sand from snowy roads, a pre rinse is not a bad idea. But you will be amazed at how much less marring is created in the paint by using Optimum No Rinse (Optimum No Rinse (ONR)), and how much dirt it can safely handle. Two buckets are fine if you put one on each side of the car for convenience, but only one is needed. Each time you dip your wash medium into the bucket, the polymers encapsulate the dirt and pull it down to the bottom of the bucket. A lot of marring of a cars paint happens when you dry the car. A traditional wash leaves only water on the car which has no lubricity. ONR still has the polymers left water drops left behind on the car. ONR also has so many other uses such as an interior cleaner, and window cleaner. Another great thing is you can wash the car right in the garage and make no run off! I could go on and on but I don't want to sound pushy or overbearing. I hope you can feel my sincerity come through in my answer.