For most interior walls, a roller is the main workhorse. It covers large areas quickly, spreads paint more evenly, and leaves a consistent texture. That’s why professionals lean on rollers for the big surfaces.
Brushes still have an important role. You need them for “cutting in” – painting along edges, corners, around switches, windows and trim where a roller can’t reach properly. A good 2–3 inch angled brush plus a medium-sized roller is a classic combo.
If you try to do entire walls with only a brush, the job takes much longer and can end up with visible brush marks. If you try to rely only on a roller without careful edge work, you get messy borders and paint where it shouldn’t be.
So it’s not either/or. Use the roller for broad strokes and the brush for details. Together, they give you a smoother, more professional-looking finish with less effort.