Have no experience with rugs on tile. I will say, however, that when we installed our (sealed) ceramic flooring in our kitchen, the tile store said to seal the grout with 10 coats of the sealer (as heronlady mentions). I did that tedious job but trust me when I say it has paid off wonderfully. It is 20+ years later and that sealer is still doing it's job. Doesn't hurt that we used a dark brown grout - which I still love and would not change. But, the grout is still shiny, indicating it is still there and doing it's job. Nothing stains my grout and clean up is a breeze.