Why do one section at a time?
 

On most waxes and sealants it says do one section at a time. But with a wax like Pinnicle you can do the whole car before you have to buff.. Any thoughts....

Depending upon the product, some are better when they sit a little longer on the paint before removed. I know when I wax my car, I usually do the whole car with Meguiars NXT before I take it off. But when I wax with P21S, I do 1 panel at a time because that wax does not need as long on the paint. Don't know if there's any 'chemical' reason for it, but I'm sure it's best to follow what each individual manufacturer says to do for their product.

Be the car??

oops typo lol... was=wax ;)

Each sealant or wax is different in how it bonds with or 'sets up' on the paint. Zaino, for example, requires that you do the whole car and then ensure that it has had time to dry before you buff it off.

I've found in the past that some of the cheaper waxes become really hard to buff off if I let them sit for a long time.

You will follow the manufacturer's instructions. And you will like it. ;)

FYI
The length of time required for the product to set up depends on the solvent package in the wax. Mineral spirits are typically used but other can be added to accelerate drying. These waxes typicaly do not chemically bond to your paint, which would risk damaging your clearcoat. Also the cheaper waxes do not have plasticizers/spreading agents (i.e. silicones) that help them buff easier.

Most waxes (not polymers) have to be done in small sections at a time because if you let them stay on too long you'll have a tough time removing the residue.

I use Zaino and apply it to the entire car and let it sit for anywhere between 30 mins to two, three, or more hours , depending on what else I might be doing, and it comes off with very little effort.

just RTFM and you wont have any problems ;)