Open strings
Buzz that disappears when the string is fretted points attention toward the nut end, string seating or related geometry.
Frets 1–5
Lower-fret buzz is a strong reason to measure neck relief before raising the bridge.
Middle of the neck
Relief and action both matter here. Establish both measurements before choosing an adjustment.
Above the 12th fret
Upper-neck buzz can expose low action, fret irregularity or neck geometry after relief has been established.
One string or one tiny area
A localized symptom is less consistent with a whole-neck problem. Inspect the string, saddle and neighboring frets before changing global setup.
Everywhere
Widespread buzz often means the setup is simply too aggressive for the guitar or the player's attack. Judge the result through the amp as well as acoustically.
Record the baseline, change one thing, retune, and test again.