You can polish your floors after every 2 to 3 months by applying Bona hardwood floor cleaner. Remember that using this cleaner depends on the number of traffic rates on the flooring, whether or not the hardwood is finished properly, as well as the quality of protection you give the surface layer.
If the place has high traffic all the time, the interval can be minimized to 1 month. If the flooring is unfinished, do not use any sorts of hardwood floor cleaner. As these types of floors are too delicate, they need special treatment.
Remember, though the solution of water and soap are often used to clean the finished floorings, they might destroy unfinished wood floorings because the moisture allows mold to grow and eventually warps the wood. In this case, you can rub mineral spirits across the wood using a cloth instead.