Taking Care of your Car’s Exterior
A key part of preserving a vehicle’s exterior is to treat it with wax or sealer.  Both types of products will protect your paint against moisture, ozone and ultraviolet. Sealers, which are typically petroleum based and contain silicones, last much longer than ordinary wax. But the difference between these two products is becoming less, because waxes have begun contain other ingredients designed to extend protection, such as silicon.
Rubbing wax or sealer on the car’s body will result in much better protection than the kind that is sprayed on.   Car wash waxes look nice temporarily, but don’t provide lasting protection.
Newer cars and trucks do have what’s called a "base coat, clear coat" finish. Over the base color coat of paint is a layer of clear paint to provide added shine and protection.  There may be information saying it is not necessary to wax or seal the vehicle because of this.   Still, it won’t hurt anything -- provided you use a product that is designed for this type of finish.  Wax or sealer for a base coat, clear coat finish should contain no abrasives or polish. Abrasives are often added to wax to remove the oxidized layer from the surface of the paint. When the wax is applied, it has a polishing effect that helps shines up dull, faded paint. It works great on solid color finishes, but not clear coated finishes because it scratches and dulls the clear coat.
Here are the basic steps to applying the product:
   -Read and Follow the written instructions.
   -Wash and dry the vehicle before the wax is put on .
   -Don’t wax in the direct sun during the heat of the day. Waxing in the shade or when the sun is low is 
      best.
   -Use a clean, soft, damp rag to apply the wax or sealer.
   -Avoid getting any on the glass or on matte black finished molding.
   -Apply wax to a small area, and let it dry before wiping and buffing. Then move on to the next area and
      repeat until the job is done.
   - Elbow grease works best. Power buffers are faster, but require skill to do a really nice job.
   - You will know when to re-wax when water no longer beads up on the finish when your vehicle is wet.

Keeping a coat of wax or sealer on a vehicle is the most important thing to do to keep the exterior looking good and protecting it from the elements.