There is a link on the site to Setting Your Post that will illustrate the preferred method for setting your posts, and make the difference between a post that last 30-40 years and a post that begins rotting the moment it is set into the ground.  Your installer will likely object to this method.  But then your installer will also be one who recommends pressure-treated posts, laced with arsenic and poisons that distract bacteria and rot from getting a foothold.  But, logical minds understand that anything that kills bacteria is not exactly healthy to humans nor the ground water tables it slowly infects.  Nor your children running their hands against such a post and then their hands drawn to their mouths and then a flurry of young budding white blood cells called into action to fight off the threat to the young body’s good health.  Just follow the suggestions we offer for setting your posts and remind your fence contractor that he is working for you and you have no interest in setting posts that need to be replaced several times over the life span of your prowell fence.