Most prefinished flooring has beveled edges and ends, which protect the finish from chipping during installation and hide unevenness that would be sanded smooth on unfinished wood. When installed, the bevels form a small groove, some as deep as ⅛ inch; others have barely noticeable micro-bevels. Keep in mind that deep grooves can collect dust and dirt and be a pain to clean. You can also opt for bevel-less "square-edge" flooring that mimics the look of site-finished boards. These work best when the subfloor is perfectly flat; otherwise you may see exposed edges.