I am getting mixed results from 3 different people I got advice for my driveway. Over a period of 20 years my driveway has sunk about a foot or so and I decided to just lay dirt and some gravel on top. Now I am ready to get someone to pour some concrete to make a sturdier driveway. I asked a few people and here is the top 3 things I was told. 1. If the original drive way had a few cracks in it then the new driveway will be fine. 2. You need to take up all that dirt/gravel and crack up that entire driveway then put the dirt back on top. 3. You need to take all of that old drive way completely out. So I am confused on what to do. The driveway is 17ft by 22ft. If I do not rip out or crack up the old driveway what is the worse that can happen?