Assuming that you have a urethane finish (either oil-base or waterbase), keep the floors clean and free of dirt, grit and sand by sweeping or dust-mopping on a regular basis. If you vacuum your floors, make sure that you use an attachment designed for hard floor surfaces, and that this attachment does not have any rough surfaces which could mar the finish. You will periodically need to lightly damp-mop your floors to remove food spills, muddy footprints, etc. When you do so, AVOID USE OF ANY PRODUCT CONTAINING WAX, OIL OR ACRYLIC. Any oil soap, spray dusting aid, or other floor care product containing wax, oil or acrylic can leave a residue on your floors which can impair adhesion of future coats of finish. Use of mats at exterior doors, area rugs or runners in high traffic areas, and felt glides on furniture legs will also prolong the finish. An additional coat of finish, referred to as a maintenance coat, is required to replenish the finish that will wear off from normal abrasion from foot traffic. There is no universal interval between maintenance coats, since the amount of foot traffic and how clean you are able to keep your floors will determine the finish life.