In many areas of the US, having mud flaps on dually vehicles is not just good sense, it is the law. Texas, for instance, mandates that all dually rear wheel drive vehicles have them. There are many other states with similar laws. Besides the legalities involved, replacing your OEM dually mud flaps and brackets once every two to three years is a good idea for many reasons.First, by doing this it helps protect your truck from the damage caused by road debris, water and salt. Road debris can fly out and scratch, dent or ding your truck quite easily. Road spray, even during the warm months of the year, can be a hazard to paint. During the winter there is often road salt mixed with the snowmelt, ice and rain, which can eat away your paint in a very short time.Second, by replacing your mud flaps and brackets regularly will also help keep down rust, corrosion and dirt build up on the under body of your vehicle. Rubber can dry rot and crack, this is a safety concern.Thirdly, you are protecting other cars driving behind and along