Having worked at a dealership, I know most detail departments simply pull off the protective shipping tape or cover, wash the car and vaccum it and apply a thin coat of wax and slap on some tire goop. One dealership I worked at had two of the best detailers I have seen and they took a lot of pride in their work. They really cleaned the car initially and made sure it was perfect and did the same at delivery. Two class act guys. They are the exception to the rule.
However, whenever I get a new car, I wash it thoroughly the next day. I wait about 90 days and clay bar the car, go over it with Swirl and Haze Remover, Revive Polish and Buttery Wax. My wife thinks I am nuts, but when I was done with her car, she was happy.
One thing to understand is you don't know and no one will tell you how long the car sat before being shipped, sat after being received at the dealer before prep and then how long it sat on the lot.
You just got a new car. You will have it for the near future. Why not take the time and make it look good from day one? When cars sit at the port or what not, they are sitting there and ignored. No one goes around and washes them every week or two. They come off a truck or boat, sit in the elements for who knows how long, then off to the dealer, again to sit for who knows how long.
One other thing to think about is your paint warranty. This also allows you to catch anything the day after delivery. It is easier to make the dealer pay for a little chip, scratch or ding just after picking it up versus even a week. If you have something in the paint and after a year or two, it has become so bad the manufacturer will deny any claims and fall back on the neglect side of it. Manufacturers like VW, Volvo, Audi and Porsche take a lot of pride in their paint work and have high customer service levels and they may be willing to help out. Why run the risk, though.
Simply put...inspect the car the day after with a good wash. Clay, polish and wax 90 days later. Save the potential headache.
My 2 cents.