Although they are very similar, there are some differences between gloss and semi-gloss interior paint. Semi-gloss paint is not as shiny as gloss paint, so choose gloss if you’re after a “wet look” shine. While any glossy paint -- semi-gloss included -- tends to show imperfections such as scratches and dents, know that the glossier the paint, the more obvious imperfections will be. An advantage to glossier paint is that it dries to a hard shine, which stands up to scrubbing and wiping better than less glossy options.
Because exterior moldings must withstand the elements, paint durability is important. Although high-gloss paint is more durable than other sheen choices, many homeowners prefer flat or satin options on the exterior of their home. High-gloss paint is very reflective and can have a plastic look, while semi-gloss is somewhat shiny and less reflective. Painting your front door with glossy paint is a good way to draw light and attention to this focal point.
Generally speaking, the glossier the paint, the more durable it is and the easier to wash. If you'd like your paint to form a hard, protective layer over your exterior trim to shield it from the sun, rain and snow, then go with a high-gloss paint. If you're painting trim or cabinets in a kitchen, consider using a high-gloss paint, as you will be able to wipe or scrub cooking messes or spilled milk. Semi-gloss paint does have a certain degree of durability and washability, but not as much as a high-gloss paint.
Know that the glossier the paint finish, the less coverage each gallon of paint will provide. While you may be able to complete a flat or eggshell paint project with two coats, the same project may take three or four coats of a gloss paint. It's also helpful to know that when it comes time to repaint, the shinier the paint, the more you'll have to sand the molding to get good adhesion from the new paint.