What doormats do is to effectively catch grit, dirt, dust and other abrasive materials which are dragged into the house from the outside on the soles of your shoes. When you wipe your feet on your doormat, you wipe off all the abrasive materials which could potentially damage your floor.
You need to get doormats for all the main entrances of your home, including back doors and side doors as well as the front door. Even a very small doormat placed at each of these points in your home can do wonders when it comes to protecting your wood floors.
Doormats arent only practical and functional, however. They can also be highly attractive, depending where you shop and how much you have to spend on them. Many places which sell modern rugs also sell doormats in many attractive and fun designs and patterns. If you want, you can even get doormats with custom slogans on them.