Materials

Because most of the cost of a paint job is in the labor, it normally does not make sense to use anything but the best materials.  Of all the obvious advantages to using a quality product, extending the lifetime of the paint job is the most important.
For an exterior, almost always we need more paint on the wood.  Usually, a film the size of a thick piece of paper, 3-4 mils, stands between your wood and the elements.  Two coats of a good product can go on 10 mils thick and withstand things like carpenter bees.
High maintenance surfaces like decks,  need all the help they can get.  We use either a high solids (96%) stain like TWP or a lifetime coating called Restore.

Materials