High gloss interior paint is common, especially in high-traffic areas, because it cleans easily. It's also used often for trim, furniture and accent pieces. While high-gloss exterior paint is not typically used for covering entire walls, it can be used for eye-catching accents on doors, window frames, shutters and trim. It also can highlight a very contemporary building with steel trim or metal exterior pieces.
Most exterior homes are painted with a flat finish. While the paint comes in oil and water-based formulas, water-based is the most widely used in contemporary homes, as it dries quickly and requires less cleanup. Both oil- and water-based pigments are available in a flat finish that hides cracks, splintering and other imperfections very well, especially on older wood.
If you're trying to restore a historic home or capture a vintage style, further considerations exist. Many exterior paints, for instance, were made using casein, or milk, as a base. This meant that the pigment was very flat. Contemporary milk and latex paints offer color and finish options to match those of the past. Exact colors and finish will depend on the style of home.
Flat and high-gloss paints typically require slightly different application methods as well. High-gloss paints reflect and highlight every little dimple and dent, so smooth, even application is essential for best results. Flat finishes tend to be more forgiving, and not every brush stroke or roll will show up. High-gloss paints typically require several layers for a silky smooth look.