Guitars and basses: check neck, bridge, tuners and hardware

Changes in action, intonation or tuning stability can have several causes.

Inspect the bridge, saddles, tuners, screws, strap buttons and moving parts before making adjustments. If something has loosened, identify the cause and use correct tools without forcing threads or screw heads.

Work on the truss rod, nut and neck geometry requires greater competence. If you do not understand the system, professional setup is preferable to a sequence of random corrections.