A guitar setup is the process of adjusting a guitar to ensure optimal playability and sound quality. This involves checking and adjusting the truss rod, which affects the neck's curvature, and setting the string height, or action, to make it comfortable for playing. Additionally, a setup includes intonation adjustments, ensuring that the guitar is in tune along the entire fretboard. Other aspects may involve adjusting the pickup height and checking for any fret buzz. Regular setups can enhance a guitarist's experience and prolong the instrument's life.