Tiles get dull really quick because they face heavy foot traffic. To keep them looking clean, beautiful and shining you need to get them some good cleaning every 12 months at the very least. And if the foot traffic is REALLY heavy, you might need the cleaning every 6 months. Dull tiles in your property, be it outdoors or indoors, will give your visitors a really bad impression. Not to mention dull tiles mean dirty tiles which can be compromising your health as well. You could get sick with a range of diseases from mild allergies to severe infections.