It totally depends how dirty the vehicle is, and how big the clay bar is. I like a nice big 6 or 8 ounce clay bar because I have big hands and it's easier to hold. I can usually clay my truck at least 4 times before I throw the clay away. But that's kind of overkill. You can probably get twice that many uses out of most clay bars. The clay bar should be fine as long as you can fold and knead the clay and none of the old contaminants show up.