Mats and rugs trap a lot of dirt, so shake them out often and clean them regularly. Movement of chairs and tables can cause excessive wear on your floor finish. Felt protectors minimize this wear. Replace narrow furniture glides with wider substitutes. When moving furniture that does not yet have furniture glides, either pick it up off the floor, or slip a cloth or heavy sock under each leg to avoid damaging the floor.
Excessive humidity can cause wood fibers to swell, creating cracks in the finish.
Excessively dry conditions can cause cracks between the floorboards. Depending on which problem you encounter, install a humidifier or dehumidifier. If it is not formulated for hardwood floors, don't use it. After application, the water evaporates and leaves a glossy coat of finish which will discolor over time, requires repeat applications, and is not compatible when future recoating of your floor is required. Never pour water or allow water to puddle on your hardwood floor.