Do I need a monitor riser or a monitor arm?

A riser is a fixed shelf that lifts your screen to eye level and usually adds storage underneath; an arm clamps to the desk and lets you move, tilt and rotate the screen freely. Across the reviewer consensus, risers are recommended for users who want ergonomics on a tight budget, and arms are recommended for anyone with curved or ultrawide screens, dual setups, or a need to clear desk space.