Latex paint is the favorite for most painted exterior surfaces because it's easier to use and more environmentally friendly than oil-based paint. Latex is more elastic and remains flexible when dry, so it won't crack as the materials to which it's applied expand and contract. Oil-based paint becomes brittle with age. Latex paint also doesn't fade as much. Latex permits interior moisture vapor to pass through, so it is less likely to peel due to moisture problems. You can apply a latex topcoat over either latex or oil-based primer.

On a few surfaces, alkyd (oil-based) paint may be a better choice than latex. For example, if a house has numerous coats of alkyd paint, it's generally best to stick with alkyd. Believing that alkyd-painted surfaces are generally easier to clean and have more sheen than latex paints, some professionals use latex on the body of the house but prefer to use an alkyd finish on the trim or other high-contact areas, such as doors. The advantages of latex outweigh the purported advantages of alkyd-based paint in most applications.

Don't use alkyd paint over a latex topcoat. It's likely to peel off even a well-prepared latex finish because the latex expands and contracts too much for the relatively rigid alkyd film.