In a milder climate, a quality exterior paint job can last ten years or more. In metro Atlanta, seven to ten is realistic for a well-prepped job, and considerably less for one that skipped the prep. Summer sun breaks down the binder in the paint, humidity feeds mildew, and the freeze-thaw cycles of a Georgia winter open up every seam the caulk has let go of.
The first sign is usually chalking: rub your hand on the siding, and if it comes away dusty, the paint's surface has started to break down. Fading on the south and west walls comes next, then hairline cracking, and finally peeling, which almost always starts at the horizontal edges of trim and window sills where water sits.
Not every sign means a full repaint. Green or black streaking on north-facing walls is mildew, and a proper pressure wash will often bring the paint back to life for another few seasons. Small peeling spots on trim can be scraped, primed, and touched up. But once you see widespread cracking or peeling on the body of the house, painting over it just buys you a year or two before it fails again.
When it is time, the job is only as good as the prep. A full exterior repaint in Atlanta should start with a wash and a genuine dry-out, then scraping, sanding, rot repair, caulking, and priming of bare wood before any finish coat. That sequence is what determines whether you're repainting in seven years or three.