Every paint manufacturer prints a service life on the can, and every one of them assumes conditions that South Carolina does not provide. Between the UV load from June through September, humidity that rarely drops for long, and pollen that coats everything each spring, an exterior here works harder than the same paint would in a drier climate.
For most Midlands houses, a good exterior job with proper prep lasts eight to twelve years on the shaded elevations and five to eight on the side that takes the afternoon sun. That is not a defect. Direct UV breaks down the binder in any coating eventually, which is why the south and west walls almost always fail first while the north wall still looks fine.
The useful test is not the calendar, it is your hand. Rub a dry palm across the siding on a sunny wall. If it comes back with a chalky residue, the binder has broken down and the surface will not hold a new coat until it is washed. Then look at the caulk lines around the windows and trim: open joints mean water is already getting behind the finish, and that is the failure that costs real money.
Two other things worth checking each spring. Look at the bottom edge of your siding boards and the ends of the trim, where end grain sits closest to the ground, because rot starts there long before it shows anywhere else. And check the north side for a green-black film, which is organic growth that will keep spreading and will not bond with new paint over it.
If you catch it at the chalking stage, you are looking at a wash, a spot-prime, and two finish coats. If you wait until the boards are cupping and the trim ends are soft, you are paying for carpentry first. Either way, the estimate should be free and it should tell you exactly which of those two jobs you have.