Daily care for granite and marble is simple: warm water, a drop of mild dish soap, and a soft cloth. Skip vinegar, lemon-based cleaners, bleach, and abrasive powders. Acids and harsh chemicals wear down the sealer over time, and on marble they can etch the surface itself.
Marble deserves special mention because it's calcite-based, which means acids like lemon juice, tomato sauce, and wine can leave dull spots called etches. That isn't a defect; it's how marble behaves, and many people like the lived-in patina. If you want a pristine look, wipe spills quickly and use cutting boards and coasters.
Sealer is what keeps stone from absorbing spills. A quick test tells you when it's time to reseal: put a few drops of water on the counter and wait fifteen minutes. If the stone darkens underneath, it's absorbing and should be resealed. Many granites only need it every year or two; lighter and more porous stones need it more often.
Florida's humidity isn't hard on the stone, but it's hard on anything that stays damp. Wipe standing water around the sink and faucet base, keep the silicone joint along the backsplash in good shape, and use trivets under hot pans. Do those few things and your countertops will look the same years from now as the day they went in.