A family in Martinez finished a screened porch in April and spent most of the spring out there. By the middle of June they had an extension cord running across the floor from the kitchen, a floor lamp in the corner because the one overhead bulb was too dim to read by, and a box fan wedged in the doorway. The porch was built well. Nobody had asked them, early enough for it to matter, what they actually planned to do out there after dark or in August.
Electrical is the easiest thing to get right and one of the most annoying things to fix later. While a porch is still framed and open, running wire is straightforward and cheap next to everything else in the project. Once the ceiling is finished, the screen is in the frames, and the slab is poured, the same work means opening things back up.
The Fan Matters More Than the Light Fixtures
If you plan one thing, plan a ceiling fan. In Augusta humidity, moving air is the difference between a porch you use in August and a porch you look at in August. Eighty five degrees with a breeze is pleasant. Eighty five degrees of still, wet air is not, no matter how good the shade is. Moving air also makes it harder for mosquitoes to fly and land, which matters on the evening somebody leaves the door open too long.
A fan needs a fan rated box, which is a bracket built to carry a swinging load rather than the few pounds a light fixture weighs. That bracket goes in while the ceiling is open. A standard light box will not hold a fan safely, and finding out you need one after the ceiling is closed up is exactly the retrofit you were trying to avoid. Fans in a porch should also be damp or wet rated depending on how exposed the spot is, since ordinary indoor fans corrode here and the blades warp.
Outlets: Count What You Need, Then Add Two
People underestimate this consistently. Think through a specific ordinary evening instead of a general idea of the space. Phone chargers. A lamp. A fan, if it is not in the ceiling. A speaker or a television. A slow cooker or a coffee maker if meals happen out there. A space heater in January, which pulls enough current to matter. String lights. Then think about the vacuum you will clean the space with, which needs an outlet nowhere near where you want the lamp.
Four is not an unreasonable number for a modest porch, spread around the perimeter so nothing has to cross the floor. Outdoor and damp location outlets need GFCI protection, and if you expect to run anything substantial, like an outdoor kitchen with a fridge, its own circuit is worth the small additional cost while the walls are open. Two or three heavy draws sharing one circuit with everything else is how you learn where the breaker panel is.
Switch placement is worth thirty seconds of thought and gets skipped constantly. You want a switch at the door you come out of, and if the space is long or has two entries, a second one at the far end so you are not walking back through a dark porch to shut things off. If string lights are part of the plan, a switched outlet mounted high, near where the lights will actually hang, keeps you from running a cord down a post to a plug at floor level.
Under a Slab, You Get One Chance
For a patio, a pergola, or anything built on concrete, conduit under the slab is the decision that is nearly impossible to walk back. Before the pour, a sleeve of conduit is inexpensive and takes very little time. After the pour, getting power to the middle of a patio means saw cutting concrete, or a surface run along the outside of a post that you will look at forever.
Even if you are undecided about lighting the fire pit area, or putting an outlet out where the grill ends up, running an empty conduit to those spots costs very little and keeps the decision open. Pergola posts can carry wiring for lights or a fan, but that also works best as part of the plan rather than an addition, since the wire needs a path that does not end up on the outside of the timber.
All of this is licensed electrician work, and in most of the CSRA it is permit and inspection work as well, which is a good thing rather than an obstacle. Outdoor circuits in a wet climate are exactly where shortcuts turn up eventually.
The reason to settle it early is not that electrical is complicated. It is that the right answer depends on how you plan to live in the space, and that is a question worth sitting with while framing is still open, when it costs almost nothing to change your mind.