Call a professional before attempting repairs if:
Your furniture finish is cracking, forming a pattern resembling alligator skin or peeling.
There are deep gashes, cuts, dents or burns in the finish film.
Nail polish or polish remover has been spilled on the hardwood.
Oil-based paint has dried on the surface.
The hardwood surface is marred by magic markers.
You are unsure as to what kind of finish film (shellac, varnish, lacquer, etc.) is on your hardwood product.
There are squeaks in your hardwood floors, whether carpeted or not.