It pays to buy top-quality paintbrushes. They apply paint more smoothly than cheaper brushes, feel more comfortable in your hand, and last for years — if you care for them properly.
For example, when cleaning a brush in a container of solvent or water, don't stand it up; you'll bend the bristles. Instead, rinse out all the paint, rake the bristles out straight with a brush comb, and hang the brush to dry. You can also help the bristles keep their shape by wrapping them in a brown-paper sheath cut from a grocery bag. Secure it with a rubber band placed around the metal ferrule on the brush. Then store the brush by laying it flat or hanging it up.