The reason you need to do this is to give your hardwood flooring space to expand and contract with changes in temperature and humidity. If you fail to leave an expansion gap your flooring will have no space to expand and can easily become damaged.
When you have finished installing wood flooring, you will, no doubt, need some flooring accessories to add the finishing touches to the room. As already mentioned, you will have expansion gaps around the edge of your room. These can easily be covered over with a range of flooring accessories like: skirting board, beading — quarter round, door bars, ramps and pipe covers.
It is really important that you properly prepare your subfloor before installation. If it has not been done correctly, it can cause your flooring to become damaged. The most important things to check are whether your subfloor is flat, level, clean and dry.
Then, at least once a week you should clean your floor with a wooden floor cleaning spray and mop. This will keep you floor looking shiny and new. You can also take a few small steps to prevent damage to your new floor.
You may also want to consider the shape and size of the room. If you have a smaller room, installing wood flooring along the length can make the room look bigger. One rule that you must follow, if you are nailing the floor to existing floorboards, is to fit the flooring perpendicular to the floorboards. This will help to give strength to the flooring and keep everything stable.
If you have a busy hallway or living space then something durable like Oak might suit you. Alternatively, for a quieter room, you could choose a more delicate wood, like Walnut.