Replace when: - Water damage caused swelling or buckling in a few boards. - Deep gouge through the wear layer into the bare wood. - Pet stains (urine) that penetrated the finish. - Burn marks beyond surface. - Missing wood from impact.
Refinish instead when: - Surface scratches without depth. - Dull finish. - Minor water stains (not through to wood).
Refinishing handles the whole room at once; replacement is targeted.