Paint manufacturers like to say an exterior job lasts ten years. In the Piedmont, with long humid summers and south-facing walls baking from May through September, seven to ten is more realistic for quality paint, and less for siding that was painted over a poor prep job.
The early warning signs are chalking (a powdery residue when you rub the siding), fading on the sunny side of the house, and hairline cracking along trim and fascia. Peeling and bare wood mean you're already late, and the prep work grows every season you wait.
The best time to paint an exterior here is spring or fall, when temperatures sit between about 50 and 85 degrees and humidity is lower. Summer painting is possible, but it means working around storms and giving each coat longer to cure.
Whatever the timing, the prep decides the lifespan. Washing, scraping loose paint, sanding, and priming bare spots is most of the labor on a good exterior job, and it's the part that keeps you from doing it again in three years.