Is it necessary to reclaim by grinding a very poor surface before placing a new gravel base or surface?
While reclamation is recommended in many cases, there are other ways to accomplish the same goal. Even a poor broken surface will act as a water barrier and can slip or act as a water stop and lead to potholes. Rather than regrinding, a grader with scarifying teeth can be used to breakup and regrade the surface. If a grader is going to be used to regrade the new material, the only extra step would be the scarifying of the surface with the grader.
Another relatively inexpensive choice would be to use a Bomag mixture to grind the surface prior to grading. This would be less expensive than a reclamation machine.