I do the whole car at once. But, it only takes about 8 minutes for me to put a a coat of Z2 on my car. A whole day to wax a car? I spent about 10 hours each over a few days doing the prep work to my & my wife's vehicles this spring. But the actualy protection only takes minutes. I use carnuba on my RX-7, but even that doesn't take a whole day once the car is clean and prepared.