Not all garage floors are the same. Not all floors are equal. When meeting with the contractor it is important to identify any issues you may have. Cracks in the concrete, badly damaged and spalled concrete, oil deposits, and waterproof issues over living space should be addressed. Most all of these problems are easily solved. Cracks can be pasted with a crack repair material, while oil deposits are necessary to remove so that installing epoxy on your garage floor bonds properly to the concrete.