There are many ways to skin this cat. None of them involve underinflating a tire.
It is perfectly acceptable to air up your tires to the pressures listed on the door sticker and running like that all the time.
It is also perfectly acceptable to find the inflation chart for your tires, weigh your truck, and inflate to the level shown on the chart.
The difference in wear and tear on the tire will be minimal. The difference in braking performance will be minimal because the front tires are inflated for the load on the front end (door sticker usually says 65PSI front, and front end weight doesn't change all that much).
