Common calls: a dark pet stain by the back door, a gouge from a moved refrigerator, a squeak in the hallway, boards that split along an old radiator line, and gaps that opened up during a dry summer. Each one has a specific fix. Stains that have gone through the finish into the wood need the board replaced. Squeaks usually need the subfloor fastened. Gaps that open and close with the seasons are normal and are best left alone; gaps that stay open can be filled or the boards can be replaced.
For board replacement we match species, width and grain as closely as possible, then sand and finish the patch to blend with the surrounding floor. On older floors with a lot of patina the repair area is often refinished in a larger section so the sheen matches.
We are honest about what a spot repair can and cannot do. If a floor has widespread wear, a full sand and refinish is usually the better value than a dozen patches.